msc of igs
TRANSCRIPT
-
7/27/2019 MSC OF IGs
1/133
Grid-connected Induction Generators with Reference to Potential Small
Power Plant Developments in Sudan
By:
SALIH AHMED OBEID SALIH
B. Sc. (Honors) in Electrical Engineering, University of Khartoum, 1981
A Thesis Submitted to the Graduate College, University of Khartoum in
Partial Fulfillment for the Award of the Degree of M. Sc. in
Electrical Power Engineering
Supervisor: Dr. Fayez Mohammed El-sadik
Co-supervisor: Dr. Kamal Ramadan Doud
DEPARTMENT OF ELECTRICAL & ELECTRONIC ENGINEERING
FACULTY OF ENGINEERING
UNIVERSITY OF KHARTOUM
February 2013
-
7/27/2019 MSC OF IGs
2/133
I
DEDICATION
I would l ike to dedicate this work to my famil y starting with the loving
Memories of my father , and to my mother Aeisha Salim I dri s who
Helped and supported me very much and to my wife Sauad Hamid
Mahadi who stood beside me all the time of thi s project and my love.
To my chi ldren, Ahmed, Elhar ith , Leena, Hammam, Alaa, and Mohammed.
Salih
-
7/27/2019 MSC OF IGs
3/133
II
Acknowledgement
I am very grateful to my supervisor Dr. Fayez Mohammed EL-Sadik
for his patience and guidance throughout the development stages of this
project. His valuable suggestions, ideas, concepts and advices are greatly
appreciated.
My thanks are also extended to the former National Electricity Corporation
(NEC) administration for their financial support during the initial stages of
the M. Sc. project.
Special thanks are due to the former gas turbine department manager,
Roseires hydro power station manager, Jebel Aulia hydro matrix power
station manager and his staff and to the technicians of Dr. Sherif thermal
power station who have greatly assisted with the experimental test bed.
Last but not least, my deepest thanks are extended to the faculty of
engineering electrical machines laboratory staff.
-
7/27/2019 MSC OF IGs
4/133
III
Abstract
The study aimed to investigate the possibility of generating small isolated
(stand- alone) or connected power to the national grid.
The studytook Jebel Aulia hydro matrix turbines as a study. The detail of the
induction generators-based project which is supplying the national grid with
30 MW of power with the minimum of running cost was described.
A hard procured testbed was installed at the electrical laboratory at the
faculty of Engineering to mimic steady state performance characteristic of the
induction generators.
The induction generator was operated above its rated synchronous speed
then the national grid was fed with 1.8 kW at three phase supply voltage of
220 V, 50 Hz and power factor of 0.82 which was further improved to be 0.98
by means of capacitor banks. The results showed that these kinds of induction
generators need neither DC excitation nor speed governing system as that
used for conventional AC synchronous generators and hence considerable
reduction of cost and size was achieved.
The survey proposed the potential sites to install small hydro power
generators to increase electric production in Sudan
-
7/27/2019 MSC OF IGs
5/133
IV
30
.
/. 1.8
0 220 0.2 0.8
. .
-
7/27/2019 MSC OF IGs
6/133
V
LIST OF CONTENTS
DEDICATION........................................................................................................ I
Acknowledgement.................................................................................................. II
Abstract ................................................................................................................ III
.................................................................................................................. IVChapter One........................................................................................................... 1
I.1 General: ......................................................................................................... 2
I.2 Sudan Installed Generation Capacity: ............................................................ 2I.3The Jebel Aulia Dam: ..................................................................................... 3
I.4 The Induction Generator Alternative: ............................................................ 4
I.5 Thesis Layout: ............................................................................................... 5
Chapter Two .......................................................................................................... 7
Grid Connected Induction Generators for Small Hydro: ..................................... 8
THE JEBELL AULIA EXAMPLE ..................................................................... 8
2.1 Technical Description: .................................................................................. 8
2.2 Reasons for the Induction Generator Alternative: ....................................... 15
2.3 System Protection: ...................................................................................... 17
2.4 Power Station Performance:........................................................................ 21
Chapter Three ...................................................................................................... 25
Equipment Procured for Laboratory Induction Generator Tests ........................... 28
3.1 General: ...................................................................................................... 28
3.2 Induction Generator Test Equipment: ....................................................... 29
3.3 Measurement of Induction Motor Parameters: ............................................ 36
Chapter Four........................................................................................................ 41
-
7/27/2019 MSC OF IGs
7/133
VI
Steady-State Performance Measurements and Calculations ................................. 44
4.1 Calculations and Measurements - Laboratory Tests: ................................... 44
4.2 Power-factor Calculations Procedure: ......................................................... 51
4.3 Calculations and Measurements for the Jebel aulia Hydro - matrix UnitsTests: ................................................................................................................ 54
Chapter Five ........................................................................................................ 64
Recommended Sites of Small Power Generation in Sudan................................... 67
5.1 Utilization of Induction Motors and old Synchronous Generators:.............. 67
5.1.1 Kilo-X gas turbine power station: ...................................................... 68
5.1.2 Burri II Power Station: ......................................................................... 68
5.1.3 Burri III Power Station:......................................................................... 69
5.1.4 Kashm Elgirba Rehabilitation Project: ............................................... 69
5.2 Potential for Small Hydro Power Schemes:................................................ 70
Chapter Six .......................................................................................................... 85
CONCLUSIONS AND RECOMMENDATIONS ............................................... 86
6.1 General ....................................................................................................... 89
6.2 The advantages of the experience:............................................................... 91
References: .......................................................................................................... 93
-
7/27/2019 MSC OF IGs
8/133
VII
LIST OF FIGURES
Figure (2.1) View of three modules of the hydro matrix turbine 8
Figure (2.2) View of one module (two turbines and generators) 9
Fig (2.3) Connection to the National Grid 10
Fig.(2.4) Another view of the feeders seen on the PLC display with Z705 and
Z8o5 11
Fig (2.5) Single-Line Diagram of Jebel Aulia S/S 12
Fig (2.6) Connection Layout of the two generators (courtesy of VA TECH
HYDRO) 13
Fig.(2.7) View of one turbo generator 14
Fig (2.8) General arrangement of Somatic S7-300 PLC 16
Fig (2.9) Layout of PV/WTG interconnected with EU and control strategy 18
Fig (2.10) The electric drawing of one module 19
Fig (2.11) Compensating circuit in 5 steps 20
Fig (2.12) Shunt capacitors connected in series with the inductance to remove the
-
7/27/2019 MSC OF IGs
9/133
VIII
harmonics (courtesy of VA TECH HYDRO) 21
Fig (3.1) 5.5KW DC motor-2.0 hp Induction Motor Generator Set 27
Fig (3.2) 5.5 KW DC motor-1.0 hp Induction Motor Generator Set 28
Fig (3.3) Power-factor Correction Capacitor Bank of 18 F units 29
Fig (3.4) Rheostats ofdifferent sizes for dc motor speed control 30
Fig.(3.5) The speed indicator of the 2 hp motor in r.pm. 31
Fig (3.6) A View of the power quality analyzer (Fluke 434) 31
Fig.(3.6) DC-Motor Prime-mover Arrangement for Induction Generator
Experiments 33
Fig (3.7) Stator winding resistance measurements 34
Fig.(3.8) No-load test display data of the 2 hp motor 35
Fig.(3.9) Locked-rotor test display of the 2 hp motor 36
Fig (3.10) Equivalent circuit of No load test 37
Fig (3.11) Equivalent circuit of locked rotor 37
-
7/27/2019 MSC OF IGs
10/133
IX
Fig.(4.1) Zero-slip 2hp motor test data 42
Fig.(4.2) Generated Power Display = 1.8 KW 43
Fig. (4.3) 2hp motor data display as generator 43
Fig (4.4) The 2hp motor as a generator with capacitor banks 44
Fig.(4.5) Active power /speed curve of the 2 hp motor 44
Fig.(4.6) Torque /speed curve of the 2hp motor 45
Fig.(4.7) Reactive power/speed curve of the 2 hp motor 45
Fig.(4.8) Power factor/speed curve of the 2 hp motor 46
Fig.(4.9) Efficiency /speed curve of the 2 hp motor 46
Fig(4.10) The 2 hp motor with capacitors in series 47
Fig.(4.11) The 2 hp motor with capacitors in series 47
Fig.(4.12) The harmonic contents of the 2 hp motor 48
Fig.(4.13) The red phase current harmonic content 48
-
7/27/2019 MSC OF IGs
11/133
X
Fig.(4.14) The yellow phase current harmonics content 49
Fig.(4.15) The blue phase current harmonics content 49
Fig.(4.16) Harmonics content of all three phase currents 56
Fig.(4.17) Wave ofthe three phase currents 56
Fig (4.18) Wave of the three phase voltage 57
Fig.(4.19) Power and energy of the induction generator 57
Fig.(4.20) Harmonic contents of the currents 58
Fig.(4.21) Volt/amp/hertz of the induction generator 59
Fig.(4.22) Display of the current waveform 59
Fig.(4.23) Display of the voltage waveform 59
Fig.(4.24) Power and energy of the induction generator 60
Fig.(4.25) Another display of power and energy of the induction generator 60
Fig.(4.26) Harmonic table for the three phase currents 61
-
7/27/2019 MSC OF IGs
12/133
XI
Fig.(4.27) Active power/speed curve 61
Fig.(4.28) Reactive power/speed curve 62
Fig.(4.29) Power factor/speed curve of the Jebel Aulia motor ..62
Fig.(4.30) Torque /speed curve of Jebel IG 63
Fig.(4.31) Simulation of capacitors connected in series 63
Fig.(4.32) Simulation ofcapacitors connected in series 64
Fig (5.1) Downstream view of Sennar dam 71
Fig (5.2) Another view of Sennar dam 71
Fig (5.3) Kilo 0 of Sennar dam 72
Fig (5.4) Kilo 77 of Jazeera Canal 72
Fig (5.5) Kilo 57 bridge of Jazeera Canals 73
Fig (5.6) Kilo 77 on Jazeera Canal (side view) 74
Fig (5.7) Kilo 57 bridge of Managil Canal 75
-
7/27/2019 MSC OF IGs
13/133
IIX
Fig (5.8) Kilo 57 on Managil Canal 75
Fig (5.9) AbuRakham dam 78
Fig (5.10) View No 2 of AbuRakham dam ...79
Fig (5.11) Kilo 22 Bridge on Rahad Canal 80
Fig (5.12) Kilo 36 bridge on Rahad Canal 81
Fig (5.13) View no.2 of kilo 36 bridge 82
Fig (5.14) Kilo 76 bridge of Rahad Canal 83
Fig (5.15) View no.2 of kilo 76 bridge of Rahad Canal 84
Fig (6.1) Typical arrangement of canal fall small hydropower station 88
Fig (6.2) Typical arrangement of small hydro power station 89
Fig (6.3) Another typical arrangement of small hydro power station .89
Fig (6.4) Kalmoni 200 kW SHP project near Guwahati in Assam 90
-
7/27/2019 MSC OF IGs
14/133
XIII
LIST OF TABLES
Table (3-1) Results of the no load test and blocked rotor test 36
Table (3.2) Rules of thumb dividing rotor and stator reactance 39
Table (4.1)The required KVAR of the capacitor for power factor correction..50
Table (5.1) Data from Elmanagil project 76
Table (5.2) Data from Aljazeera project 77
Table (5.3) Data from Elrahad project 85
-
7/27/2019 MSC OF IGs
15/133
XIV
LIST OF APPENDICES
APPENDIX A A
APPENDIX B M
APPENDIX C N
APPENDIX D O
APPENDIX E E
-
7/27/2019 MSC OF IGs
16/133
CHAPTER I
INTRODUCTION
-
7/27/2019 MSC OF IGs
17/133
2
Chapter One
I.1General:
In the National Energy Plan of 1985 and the National Strategy Plan of
1992, the power sector objectives of Sudan were formulated. The plan of a
hydro matrix power plant implementation at the Jebel Aulia Dam is fully in
line with these objectives; in particular, the emphasis on the development of
hydroelectric generation together with the provision of electricity at lowest
possible cost, which can be fully met with this technology aiming at less civil
construction, little excavation and no coffer dams, no additional land usage,
and the maintenance of existing river flow patterns.
I.2 Sudan Installed Generation Capacity:
Sudan currently has an installed electricity generation capacity of 2588 MW,
managed by the ministry of dams and electricity. It is composed of the
thermal (mainly furnace) and hydropower plants. Hydroelectric power
generation varies greatly over time, due to rainfall patterns. The maingenerating facility of hydro power is the Merowi dam located on the Main
Nile river basin approximately 430 km north of Khartoum with ten
generating units of a total 1250 MW. Roseires has an installed capacity of 280
MW, but its output varies greatly as water levels on the river rise and fall
throughout the year.
VA-Tech-Hydro Hydro-matrix coordinator Herald Schmidt said: "The
excellent business relation between NEC and VA-Tech-Hydro goes back to
1968, when NEC ordered the original equipment for the Roseires hydropower
plant. The original turbines were supplied and installed by VA-Tech-Hydro
for NEC and just recently VA-Tech-Hydro has been awarded contracts to
-
7/27/2019 MSC OF IGs
18/133
3
rehabilitate these turbines. The modernization and rehabilitation of the
turbines became necessary because of the wear and tear caused by the
aggressive and heavy silt load of the Blue Nile"1.
Schmidt continued: "The continuous engagement at the Roseires power
station has led to the formation of an informal partnership between NEC and
VA-Tech-Hydro under which VA-Tech-Hydro provides supplies, expert
services and consultations in order to effectively support and assist NEC in its
effort to maintain and improve electricity supply to Sudan's growing economy
and private consumers".
I.3The Jebel Aulia Dam:In the year 2001, VA-Tech-Hydro received its first large contract for a
Hydro-matrix power plant. The contract was placed by the former National
Electricity Corporation (NEC), the Sudanese state owned electricity producer
and distributor. The total contract value was worth 30 million Euros. NEC
awarded VA Tech Hydro with the supply of 40 Hydro-matrix power modules,
each with two turbine generator sets, for 40 of the 50 openings of the Jebel
Aulia dam on the White Nile in Sudan about 40 km south of the capital,
Khartoum. The contract also included the required mechanical and electrical
auxiliary systems as well as a new dam crane.
The Jebel Aulia dam was built in 1933-37 and is used mainly for irrigation
purposes and flood control. In March 2004 the first 20 Hydro-matrix turbines
were handed over to the customer for commercial service and have been
1Power Engineering International magazine, June 2004.
-
7/27/2019 MSC OF IGs
19/133
4
supplying electricity into the grid of NEC. Installation work on the next units
is already in full swing, every two months ten turbine generator units were
commissioned.
Full operation of the power plant was scheduled for early 2005. The new
Hydro-matrix power plant at Jebel Aulia has contributed considerably with
30.4 MW to the generation capacity in Sudan by means of environmentally
clean hydropower.
Financing was one of the key issues of the project. At the time, bank
guarantees to the satisfaction of VA Tech Hydro could not be obtained, butwith a special procedure this problem was solved. It was agreed with the
customer that periodical payments would be made, while VA Tech Hydro will
only perform according to milestone events. This procedure has turned out to
be the best for both parties and is based on the long lasting excellent
relationship and particularly with the previous National Electricity
Corporation (NEC) which is the main supplier together with the new
generation of Merowi Dam power station which is implemented by the Dam
Implementation Unit(DIU) and adding a power of 1250 MW to the national
grid of Sudan which is already having a power of 1338 MW, where an
efficient electrical energy of 30 MW has been obtained from Jebel Aulia
Hydro matrix power station as described below.
I.4 the Induction Generator Alternative:
Engine driven induction generators were ideal power sources for those
industries and farmers required to curtail their demands during the power
-
7/27/2019 MSC OF IGs
20/133
5
shortage in northern California in the spring of 19482.
The advantages of the
induction generator were: control apparatus simplicity, freedom from
hunting, neither excitation nor synchronization requirements, low fault
currents, low cost, and subsequent general usefulness in later motor
applications.
The nameplate data on most induction machines would be those of motor
ratings, and it is desirable to consider what changes must be made, if any, in
order that the machine operate satisfactorily as generator. If the speed is
driven above synchronism by the same revolutions per minute that the
machine normally operates at below synchronism, the generator will deliver
approximately rated current at rated voltage and rated efficiency. The electric
power out will be approximately equal to the rated shaft motor power. The
generator power factor will be much worse, being approximately equal to the
motor power factor times the motor efficiency.
I.5 Thesis Layout:
The aim of this dissertation project is to present a study of the potential sites
for hydropower development projects in Sudan with reference to induction
generator applications, taking Jebel Aulia Hydro-matrix project as an
example. To this end, Chapter II presents an over-view of the Hydro-matrix
experience with induction generators in Sudan. Chapter III shows the kind of
the experiments being done on the University of Khartoum Laboratory and
the equipments procured for that work and it is followed in Chapter IV by the
results of an investigation into the characteristics of grid-connected induction
2 From a paper written by OTTO J. M. SMITH with the title (Generator Rating of Induction Motors)magazine AIEE magazine, volume69, 1950.
-
7/27/2019 MSC OF IGs
21/133
6
generators in terms of capability limits and power factors performance using
a suitably-matched experimental test bed. Verification results of steady-state
performance characteristics as well as experimental findings on the installed
hydro-matrix generators are also presented in this Chapter. Chapter V
presents the results of a research into the potential of additional sites for small
hydropower developments as well as the identification of large motor
installations for possible utilization as generators in Sudan.
-
7/27/2019 MSC OF IGs
22/133
7
CHAPTER II
GRID-CONNECTED INDUCTION GENERATORS FOR SMALL HYDRO
WITH REFERENCE TO THE JEBEL AULIA EXAMPLE
-
7/27/2019 MSC OF IGs
23/133
8
Chapter TwoGrid Connected Induction Generators for Small Hydro:
THE JEBELL AULIA EXAMPLE2.1 Technical Description:
The Hydro matrix power plant in Jebel Aulia consists of 80 turbine-generator
sets, which are installed in 40 modules by pairs as seen in figure (2.1)
Figure (2.1) view of three modules of the hydro matrix turbine
-
7/27/2019 MSC OF IGs
24/133
9
Figure (2.2) view of one module (two turbines and generators)
Each module is equipped with two submerged, 380 kW horizontal propeller
turbines. Each turbine has a 1120 mm diameter, three-bladed runner
precision cast of aluminum bronze. Additionally, the scope of the VA Tech
Hydro contract contains all mechanical and electrical auxiliaries. NEC
carried out local activities for the accomplishment of the contract since Hydro
matrix makes use of the existing dam structure, only very minor civil
construction is needed. This is one of the predominant advantages of the
technology. The Hydro matrix modules are shipped to the Jebel Aulia dam
where they are installed into the existing water passage
the on/off operation of the turbines will be accomplished by means of the
-
7/27/2019 MSC OF IGs
25/133
1
existing control gate. Both turbines of one module will be turned on or shut off
simultaneously. The gate has only an open and closed position.
Ten of the 690 V asynchronous generators feed into one common container
type generator switchgear substation. This arrangement is one out of eight
lots. Each one of these substations has its own control and step up transformer
and also includes the reactive power compensation.
A total of eight of these substations are installed at the dam side, on the
opposite side of the machines and handle the total plant output of the 80 units.
From these eight substations, individual 33 kv cables run to a 33 kv stationlocated beside the river. The whole power plant is managed from a central
plant control station. With this concept it is possible to operate each lot
independently from the others. The power station is connected to the national
grid through two 33 kv feeders feeding the Jebel Aulia substation by two
breakers named Z705 and Z805 as shown below in fig. (2-3)
-
7/27/2019 MSC OF IGs
26/133
220KV220 KV
110KV110KV
33KV33KV
Z705Z805GitainaJebel
Jebel Auila power station Bus bar
SUNDUS
33KV
33K
V
Jebel
Gitaina
Fig (2.3) Connection to the National Grid
-
7/27/2019 MSC OF IGs
27/133
2
Fig. (2.4) another view of the feeders seen on the PLC display with Z705 and Z
805
-
7/27/2019 MSC OF IGs
28/133
3
Fig (2.5) Single-Line Diagram of Jebel Aulia S/S
-
7/27/2019 MSC OF IGs
29/133
4
For emergency power supply a diesel generator unit is installed and acts as a
backup power supply in case of loss of net voltage for the control gates gear
motors and the module crane.
The induction generators as seen on (Figure 2.6) below
Fig (2.6) Connection Layout of the two generators (courtesy of VA TECH
HYDRO)
-
7/27/2019 MSC OF IGs
30/133
5
Fig.(2.7) View of one turbo generator
2.2 Reasons for the Induction Generator Alternative:
The induction generator has been selected for the project due to the following
reasons:
1-No need to excitation system of direct current for the voltage and reactive
power control such as that used for synchronous generators.
2-No need to electro hydraulic governor to control the speed or the generator
frequency or any kind of speed droop as that used for synchronous machines.
-
7/27/2019 MSC OF IGs
31/133
6
3-The induction generators are self-protected during surges and system
disturbances and have a very low fault current.
4- The motors (induction generators) are robust and reliable with low cost
and maintenance and high efficiency (squirrel cage type).
5- No synchronization problems of voltage, frequency and phase angle, what is
really needed ,is to have both the turbine and the generator to run at the same
direction with speed above the synchronous speed of the motor (375rpm ) and
the turbine is run with 379 rpm and then being connected to the system.
6-The compensation of the reactive power being absorbed by the induction
generators is done by means of shunt capacitors connected in steps manually
or automatically.
7-The operation and control of the hydro matrix turbines is simple and
reliable and constitutes a good and simple example of renewable energy
without pollution and complication if we consider the example of Egypt in
wind turbines at the Zafarana wind turbine fields which is used to produce
power with induction generators together with Photo Voltaic (PV) system
which is a very complicated system of inversion and power electronics (see
fig2.9).
8-The system is monitored and operated and controlled by means of a
Programmable Logic Controller (PLC) from Siemens Company (Somatic S7-
300) and is configured by the National Load Dispatch Centre (NLDC) SCADA
system by means of two servers according to the international relevant
standards and that kind of automation is very suitable for such a system as
shown below:
-
7/27/2019 MSC OF IGs
32/133
7
Fig (2.8) General arrangement of Somatic S7-300 PLC
9 - There is a standby diesel engine generator to supply the low voltage system
and the batteries and close the gates in the case of power failure.
10-The induction generator is equipped by three sensors (pt100) formeasuring the temperature of the stator winding and giving alarm in case of
high temperature and two sensors for the temperature of the bearings (DE
&NDE) and three water level sensors to protect the generator from water
coming inside the generator and also there is one magnetic pick up speed
sensor.
2.3 System Protection:
A-Differential protection.
B-Voltage monitoring (over-voltage 1&2 and undervoltage 1&2).
C-Over-frequency 1&2 and under frequency 1&2.
-
7/27/2019 MSC OF IGs
33/133
8
D- Over d current protection.
E-Earth-fault protection.
F-Over-load protection.
G-Reverse-power protection.
H-Over-speed protection.
I- Monitoring of stator windings temperature and bearings.
J- Leakage water level.
-
7/27/2019 MSC OF IGs
34/133
9
NN=Neural Network.
PV=Photo Voltaic cells.
EU=Electric Utility.
Fig (2.9) Zafarana Wind field schematic diagram with photo voltaic cells in
Egypt
-
7/27/2019 MSC OF IGs
35/133
21
Fig (2.10) the electric drawing of one module
-
7/27/2019 MSC OF IGs
36/133
2
Fig (2.11) compensating circuit in 5 steps
2.4 Power Station Performance:
The power station is considered to be a very good example of efficient
electrical energy, where it is friendly to the environmental surroundings with
a very low cost and good price of MWHR (46.7 Sudanese pound), please refer
to appendix (B ) although it is totally shut down for four months as the head
goes below the required designed head (less than 1.88 m ) ,in spite of that
outage the performance has been found in good situation and somemodifications have been done to make better performance such as :
A- The total harmonic distortion (THD)of both voltage and current were
found very high at the beginning of the power station start due to the
-
7/27/2019 MSC OF IGs
37/133
22
capacitor banks which are used for the power factor correction and
reduction of the reactive load burden of NEC (i.e. THD is above 50 % )
and that happened during the switching operation of capacitor banks
which are selected in five steps to raise the power factor from 66% up to
98%,and that high distortion obliged NEC to ask the help and advices of
their consultant Dr. Abdelrahman Karrar,who is the NEC technical
consultant and advisor, to study that problem where he stated that the
harmonics are not from the generator winding design which is well
designed and it is coming from NEC power system and the capacitors
which are nonlinear load. The problem was solved by VA TECH through
the insertion of passive filters (inductance) being connected in series with
the capacitor banks and it was almost vanished and the harmonics are no
longer
seen,
please see
figure
(2.12)
-
7/27/2019 MSC OF IGs
38/133
23
Fig (2.12) Shunt capacitors connected in series with the inductance to remove
the harmonics (courtesy of VA TECH HYDRO).
B- Since all the generators are submersible and have got no heaters to prevent
condensation ,some water leakage are trapped inside the generators and the
water is detected by some sensors and cause tripping of the generator and it
was solved by means of drain pipes and small pumps, but it sometimes it
causes condensation and weak insulation of the stator windings, and that
problem was solved later by means of vacuum pump and heating system and
further on, a new modification of heating system through the generator
winding is proposed by NEC and Andritz Hydro will be going to implement
it as shown on the diagram below which is a proposal of heating the module
-
7/27/2019 MSC OF IGs
39/133
24
With the use of direct current (DC) supply.
C- Some contactors of both the generator and the compensating circuit are
subject to failure and damage and burning from time to time during the
system disturbance and that was solved by new modification of the sequence
order of the system tripping by tripping of the capacitor bank at the first time
and keep the generator contactor closed, however, on real fault the contactor
-
7/27/2019 MSC OF IGs
40/133
25
shall be tripped in normal condition and hence protecting the generator from
over voltage which is the most dangerous situation.
D- Connection of the power station with the main National load Dispatch
Centre (NLDC) through the SCADA system and Siemens PLC automation for
better communication.( only one channel is used and the other one could not
be operated).
E-The reactive power of the induction generators at the beginning of the
scheme is fed from the (Majarous) substation, through feeders of 33 KV, as
the substation is supplied with 110 KV and now it is fed from Jebel Aulia
substation which is supplied with 220 KV, where the problem of the voltage
drop is solved.
F- The power cable of the hydro matrix generator is not a submersible one
and sometimes it is subject to some damages and cut on the cable which leads
to weak insulation of the whole system (the cable +induction generator) that
problem is treated and solved by means of using a special kind of shrinkable
heating to seal the cable not to allow water to go inside the live conductors.
G-Runner Chamber and Draft Tube Problems:
Some cracks and cavities appear in the runner chamber and the draft tube
and many discussions with VA-TECH and the mechanical engineers of the
power station were made and finally they came to a solution of using the
coating devices which have the name (IRATHANE 155) and previously with
(CRAME-KOT) and the company agreed to turn out the existing mild steel
plates and install new stainless steel sleeves as already being fixed for the
runner chambers as reliable and durable solution and by making new plates
of stainless steel being welded above the original one.
Finally we hope that our company, the Sudanese Hydro Power Generation
Company Ltd (SHGC) with coordination of the ministry of dams and
-
7/27/2019 MSC OF IGs
41/133
26
electricity could consider more projects and schemes similar to Jebel Aulia to
be implemented, like Sennar dam deep sluice gates and the Jazeera, Managil
canals and Elrahad canals as some studies which are included within this
thesis are done on this matter by the former NEC and the ministry of
irrigation (MOI) and the Jazeera scheme board. The Andritz Hydro company
has manufactured another design of hydro matrix with new system called
Straflo matrix which is mainly a hydro matrix turbine, but with a
synchronous generator that has a permanent magnet installed on the rotor of
the generator, although, there will be no need to compensating capacitors but
a further study and comprehensive load flow shall be done to select the best
design of the permanent magnet and our company has to decide which option
to select.
-
7/27/2019 MSC OF IGs
42/133
27
CHAPTER III
EQUIPMENT PROCURED FOR LABORATORY INDUCTION
GENERATOR TESTS
-
7/27/2019 MSC OF IGs
43/133
28
Chapter Three
Equipment Procured for Laboratory Induction Generator Tests
3.1 General:
This Chapter describes the set of experiments conducted at the Electrical
Machines Laboratory of the University of Khartoum aiming at investigating
the steady-state performance characteristics of grid-connected induction
generators. The equipment for these tests were obtained with considerable
effort as the available laboratory test beds of motor-generator sets were
thought unsuitable in terms of prime-mover power /generator ratios. Two
different motor-generator sets of higher ratios were procured with the help of
a NEC donation of a DC prime-mover motor and the technical assistance
received with respect to mechanical couplings. Digital multi-meters and power
quality analyzers were also made available for the active and reactive power
recordings under different operating conditions, including those of the
capacitor-compensated system aiming at power-factor improvements.
Calculations results of power-factor correction capacitors ratings based on
recommended practice tables are presented in this chapter.
-
7/27/2019 MSC OF IGs
44/133
29
3.2 Induction Generator Test Equipment:
Fig (3.1) 5.5KW DC motor-2.0 hp Induction Motor Generator Set
-
7/27/2019 MSC OF IGs
45/133
31
Fig (3.2) 5.5 KW DC motor-1.0 hp Induction Motor Generator Set
-
7/27/2019 MSC OF IGs
46/133
3
Fig (3.3) Power-factor Correction Capacitor Bank of 18 F units
-
7/27/2019 MSC OF IGs
47/133
32
Fig (3.4) Rheostats of different sizes for dc motor speed control
-
7/27/2019 MSC OF IGs
48/133
33
Fig.(3.5)the speed indicator of the 2 hp motor in r.pm.
Fig (3.6) A View of the power quality analyzer (Fluke 434)
-
7/27/2019 MSC OF IGs
49/133
34
The equipment acquired for the experiment consists of M-G sets, resistor and
capacitor banks assemblies and measuring/recording instruments. These are
shown in Figures (3.1 up to 3.6) where the corresponding specifications are
given in Appendix (D).The acquisition of the M-G sets shown in Figures (3.1
and 3.2) was in particular a hard and time-consuming task. In this respect, the
donation by NEC of the DC motor drive and the technical assistance received
with the alignment and coupling of the two experimental motors is greatly
acknowledged.
Since the prime mover is designed to run with a speed of 2900 rpm it is only
possible to decrease the speed by armature control and we are able to do that.
Many shots of operations were made for running the induction motor as a
generator and could be seen on the results obtained and the application of
capacitor banks (Figure 3.3) (shunt type) for both connection of star and delta
and by the use of the compensation table which is attached to appendix (C)
and even the attempts of connection of the series capacitor as explained.
It is worth mentioning that during the tests of the series capacitors an accident
happened which caused a complete failure of the coupling associated with a
very high noise and after investigation and inspection it was found coming
from the utility supply which was received at that time in a reverse direction
and that was a mal operation by (NEC) operation and distribution staff after
a maintenance work. That failure caused us too much time to find another
motor and to make new coupling at the industrial area of Khartoum North.
-
7/27/2019 MSC OF IGs
50/133
35
Finally we get a new induction motor (squirrel cage) with a power of one hp.
and being driven by the same 5.5 KW dc motor the schematic diagrams of
both the dc motor and the induction motor can be seen on figure (3.6)
Fig.(3.6) DC-Motor Prime-mover Arrangement for Induction Generator
Experiments.As it is explained previously all our tests and experiments are done with that
kind of grid connected generators, where the reactive power needed for the
magnetization is obtained from the grid and due to the non-availability of
Induction motor schematic diagram
5.5 kw dc motor coupled with the induction motor
-
7/27/2019 MSC OF IGs
51/133
36
some devices and equipments such as the dynamometer or the LABVIEW
equipments with its software and we started looking for dc source capable of
running the 5.5 kw dc motor but we could not find it in Khartoum, some
tests are simulated by MATLAB program such as series capacitor and speed
torque curve and reactive power curve and the power factor to slip curve as
can be seen on the results chapter
3.3 Measurement of Induction Motor Parameters:
The 2 hp induction motor parameters which are xs,xr,rs,rr,xm and rc were
measured by means of the following tests:
1-The DC test for stator resistance by means of battery voltage of 12 v dc and
a limiting resistor of 8 ohm as shown below
Fig (3.7) stator winding resistance measurements2-No load test
3-Locked rotor test
The stator winding resistance was obtained by means of a dc source from a
car battery which was equivalent to 12.87 v dc and a limiting resistor of 8 ohm
and by taking three readings as shown below
-
7/27/2019 MSC OF IGs
52/133
37
1-2rs=2.56 v/1.121A = 2.384 ohm
2-2rs=2.59 v/1.124A = 2.304 ohm
3-2rs=2.59 v/1.126 A= 2.300 ohm
The average value of rs is (2.384+2.304+2.300)/6 = 1.165 ohm. And by the
display of the fluke meter which is shown below seen on figure (3.8).
Fig.(3.8) no-load test display data of the 2 hp motor
DPF=Distortion Power factor
-
7/27/2019 MSC OF IGs
53/133
38
Fig.(3.9) locked-rotor test display of the 2 hp motor
And the table (3-1) is showing the measured values of the No load test and the
locked rotor test which was done by supply voltage of 50 Hz in frequency and
reduced voltage as shown below:
Table (3-1) results of the no load test and blocked rotor test
S
Speed
in
rad/sQPVavIcIbIaType of test
0.63
KVA
157.08
rad/s0.57 KVAR0.26
KW231.3 V1.5
A1.7 A1.5 ANo load test
0.96
KVA0
Rad/s0.85 KVAR0.45
KW77.16 V7.1
A7.2 A7.3 ABlocked
rotor test
-
7/27/2019 MSC OF IGs
54/133
39
It is worth mentioning that the locked rotor test is done by means of variable
transformer of 1500 VA.
Fig (3.10) equivalent circuit of No load testAlso the figure below shows the locked rotor equivalent circuit
Fig(3.11) equivalent circuit of locked rotor
From the figures shown above the following calculations are done for the
parameters measurement
From the No load test the following equation can be used
(3.1)
Average value of IO is (1.7+1.5+1.5)/3=1.566 A
Znl =(0.57/ (1.5666)2)*1000 /3 = 77.48 ohm
The above mentioned value is equivalent to X1 +XM
-
7/27/2019 MSC OF IGs
55/133
41
The stator copper loss is equal to
PSCL =3IO2R =3*1.5666*1.566*1.165 = 8.57 w (3.2)
Therefore the no load rotational losses are
Prot =PinPSCL =260 -8.57=251.43 watts
From this value we can find out the Rc resistance which is equivalent to:
Rc = (Vph)2/Prot/3 = 17834.3/251.43/3 =212.8 ohm (3.3)
From the locked rotor test,
Iav= (7.3+7.2+7.1)/3 =7.2 A (3.4)
The locked rotor reactance is XLR= (Q/3)/I2
(3.5)
= (850/3)/51.84
=5.465 ohm
From the rules of thumb which is dividing the stator and rotor reactances as
it is made over years of experience since there no simple way to separate the
contributions of the stator and rotor reactances from each other.
The table below is showing the relation between stator and rotor reactance
-
7/27/2019 MSC OF IGs
56/133
4
Table (3.2) Rules of thumb dividing rotor and stator reactance
X1 and X2 as a function of XLRRotor DesignX2X1
0.5 XLR0.5 XLRWound rotor0.5 XLR0.5 XLRDesign A0.6 XLR0.4 XLRDesign B0.7 XLR0.3 XLRDesign C0.5 XLR0.5 XLRDesign D
So the values of XLRis equal to(X1+ X2) since our rotor is wound type
X1 = X2 =5.465/2 = 2.732 ohm (3.6)
The locked rotor resistance, RLR=R1 +R2 (3.7)
So the RLR= (P/3)/Iav2= (450/3)/ (7.2 *7.2) (3.8)
= 2.89 ohm
Then R2 is equal to 2.89-1.165 = 1.723 ohm
Also we can find the value of XM which is equal to 77.48-2.732
=74.74 ohmSo now we can arrange all the motor parameters as follows:
-
7/27/2019 MSC OF IGs
57/133
42
1- x1 = 2.732 ohm
2- x2/= 2.732 ohm
3- r1 = 1.165 ohm
4- r2/= 1.723 ohm
5- Synchronous speed =1500 rpm
6- motor voltage line to line =230 v
7- XM = 74.74 ohm
8- Frequency =50 Hz9 - Rc =212.8 ohm
-
7/27/2019 MSC OF IGs
58/133
-
7/27/2019 MSC OF IGs
59/133
-
7/27/2019 MSC OF IGs
60/133
45
Fig.(4.2) Generated Power Display= 1.8 KW
Fig.(4.3) 2hp motor data display as generator
-
7/27/2019 MSC OF IGs
61/133
46
Fig(4.4)the 2hp motor as a generator with capacitor banks
For the measurement of the 2hp motor parameters the following displays
were obtained:
The MATLAB displays of the 2hp motors were shown below after obtaining
the motor parameters on the previous chapter (chapter 3 and Appendix E)
-
7/27/2019 MSC OF IGs
62/133
47
Fig.(4.6) torque /speed curve of the 2hp motor
Fig.(4.7) reactive power/speed curve of the 2 hp motor
-
7/27/2019 MSC OF IGs
63/133
48
Fig.(4.8) power factor/speed curve of the 2 hp motor
Fig.(4.9) efficiency /speed curve of the 2 hp motor
0 500 1000 1500 2000 2500 30000
100
200
300
400
500
600
700
800Induction Motor
Efficiency(%)
Speed (RPM)
30
40
50
60
70
80
90
100
-
7/27/2019 MSC OF IGs
64/133
49
Fig(4.10) the 2 hp motor with capacitors in series
Fig.(4.11) the 2 hp motor with capacitors in series
-
7/27/2019 MSC OF IGs
65/133
51
And there were some other displays shown below:
Fig.(4.12) the harmonic contents of the 2 hp motor
Fig.(4.13)the red phase current harmonic content
-
7/27/2019 MSC OF IGs
66/133
5
Fig.(4.14) the yellow phase current harmonics content
Fig.(4.15) the blue phase current harmonics content
4.2 Power-factor Calculations Procedure:Table-based:
The power factor calculations were based on the table shown below:
-
7/27/2019 MSC OF IGs
67/133
52
Table (4.1) the required KVAR of the capacitor for power factor correction
-
7/27/2019 MSC OF IGs
68/133
53
The 2hp motor power factor calculation was done as follows:Although the induction motor rated power was only 2 hp which was
approximately equal to 1.5kw, and by driving the generator by the dc motor it
was noticed that the generator was very stable and no more heat could be
observed, but it was noticed that the rheostats which were rated by 16 ampere
and used to control the dc motor speed became very hot and the current was
almost equal to 25 A. Then it was seen that the power factor was equal to 0.84
with a reactive power of 1.2 kvar and by the power factor correction table
On the view of power factor correction table
It became possible to use it and do the following calculation
P (tan 1-tan2) = Q (4-1)
Where P is rated power of the induction motor, and 1 is the power factor
angle before the improvement and 2 is the power factor angle after the
correction, and Q is the reactive power needed for the correction in (VAR).
The rating of the capacitors can be obtained by the following formula
Qn =Un.In (4-2)
Where Unis root mean square (rms) value of the ac voltage applied.
In is the rms of the capacitor current.
Qn =Un.Un/Xn (4-3)
Where Xn is the capacitive impedance and equal to
Xn=1/wCn=1/2fCn ... (4-4)
-
7/27/2019 MSC OF IGs
69/133
54
Where f =fundamental frequency in Hz
Cn =total capacitance in farad
Calculation of the compensated reactive power in (vars) from 0.85 powerfactor to 0.98 power factor.
1500(0.417) = 625.5 vars
Cn =Qn/ (Un2*2*f) which is used for star () connected capacitor
And when it is used for delta () the equation is
Cn =Qn/ 3(Un2*2*f).. (4-5)
So the capacitor value is equal to
Cn() =625.5/ (220*22o*2**50) = 41.136 F
This capacitor is connected in parallel to the induction generator and the
improvement received is shown on figure (4.4) where a power factor equal to
0.98 was got.
4.3Calculations and Measurements for the Jebel Aulia Hydro -matrix Units
Tests:
The following calculations were made to find out the induction motor
parameters and it was based on the factory tests which were done on the
factory and it was as follows:
The parameters of the induction generators of Jebel Aulia
The following results are obtained from the factory tests of the induction
generators in Austria.
-
7/27/2019 MSC OF IGs
70/133
55
Now we can find the average value of the stator winding resistance
Rs= (0.007910+0.007932+0.007955)/3 =0.007932 ohm
From the no load test we can find
Zeq. = (V/3)/I. (4-6)
=2.9995 /3 with angle 88.11
=1.7317 sin 88.11
= 1.7308 ohm
=Xs +XM
The stator copper losses
PSCL=3I2Rs. (4-7)
= 3(230.04)2(0, 007932)
=1.256 KW
Im = Iosin. (4-8)
-
7/27/2019 MSC OF IGs
71/133
56
=230.04 sin 88.11 = 229.91 A
Ic= Iocos (4-9)
=230.04 cos 88.11
Rc =Vph/Ic (4-10)
=398.371/7.586
=52.63 ohm
Locked Rotor Test
Zsc =Vph/I (4-11)
= (207.7/3)/460
=119.915/460
=0.2606 ohm
=0.2606 cos
=0.2606x0.174
=0.0453 ohm =Rs +Rr
Rr =0.0453-0.007932
=0.03742 ohm
Xeq = Zscsinsc (4-12)
= 0.2606 sin 79.97
=0.2566 ohm
-
7/27/2019 MSC OF IGs
72/133
57
Xeq = Xr +Xs..... (4-13)
Xr = Xs
= 0.2566/2
= 0.1283 ohm
XM= 1.73080.1283
= 1.6025 ohm
Now we can arrange all the induction motor parameters as follows
Vs = 690 v line to line
=398.371 v phase to ground
Induction generator speed =379 rpm, which is obtained by the turbine and
above the synchronous speed.
Please note that the synchronous speed is equal to 375 rpm with total number
of 16 poles
XM =1.6025 ohm.
XS = 0.1283 ohm.
Xr/
= 0.1283 ohm.
rs =0.007932 ohm.
rr/
= 0.03742 ohm.
RC = 52.63 ohm.
We also made different displays at the power station and we got the following
-
7/27/2019 MSC OF IGs
73/133
58
Displays:
Fig.(4.16) Harmonics content of all three phase currents
Fig.(4.17) Wave of the three phase currents
-
7/27/2019 MSC OF IGs
74/133
59
Fig (4.18)Wave of the three phase voltage
Fig.(4.19)Power and Energy of the induction generator of JebelAulia
-
7/27/2019 MSC OF IGs
75/133
61
Fig.(4.20) Harmonic contents of the currents
Fig.(4.21) Volt/Amp/hertz of the induction generator of Jebel Aulia
-
7/27/2019 MSC OF IGs
76/133
6
Fig.(4.22) Display of the current waveform
Fig.(4.23) Display of the voltage waveform
Fig.(4.24) Power and Energy of the induction generator
-
7/27/2019 MSC OF IGs
77/133
62
Fig.(4.25) Another display of power and energy of the induction
generator
Fig.(4.26) Harmonic table for the three phase currentsAnd from the parameters obtained and by using MATLAB system the
following displays were obtained for Jebel Aulia induction generators:
-
7/27/2019 MSC OF IGs
78/133
63
Fig.(4.27) Active power/speed curve
Fig.(4.28) Reactive power/speed curve
0 100 200 300 400 500 600 700 800-1
-0.8
-0.6
-0.4
-0.2
0
0.2
0.4
0.6
0.8
1x 10
6 Induction Motor
ActivePower(Watts)
Speed (RPM)
-
7/27/2019 MSC OF IGs
79/133
64
Fig.(4.29) Power factor/speed curve of the jabal motor
Fig.(4.30) Torque /speed curve of Jebel IG
-
7/27/2019 MSC OF IGs
80/133
65
Fig.(4.31) Simulation of capacitors connected in series
Fig.(4.32) Simulation of capacitors connected in series
-
7/27/2019 MSC OF IGs
81/133
66
CHAPTER V
RECOMMENDED SITES OF SMALL POWER GENERATION IN SUDAN
-
7/27/2019 MSC OF IGs
82/133
67
Chapter Five
Recommended Sites of Small Power Generation in Sudan
5.1 Utilization of Induction Motors and old Synchronous Generators:
It is noticed that most of the highly industrial countries are making their best
to get use of their old replaced electric machines whether they are
synchronous or asynchronous. As an example to that on the Unites State of
America (USA) they have what is called (VAR pumping stations) which means
that their old synchronous machines are best utilized and being used as
synchronous condensers (production of reactive power) after the removal of
their old prime movers which are now replaced by new modern electric drives
or by closing the guide vanes by means of compressed air system in case of
hydro power generators. Also the induction motors can be made to operate as
induction generators since induction generators control is very simple and
need neither speed governor nor excitation system control.
If we look at the situation of our country (Sudan) we can say that we have lost
all of our old electric machines whether they are synchronous or
asynchronous. When considering the history of the electric generation in
Sudan and the industrial development of factories, we can start with different
old power stations and they are described as follows:
-
7/27/2019 MSC OF IGs
83/133
68
5.1.1Kilo-X gas turbine power station:
That power station which was used in the past for production of power and
being used for voltage control as it was made operated as a synchronous
condenser by means of an electric clutch which was used to disconnect the
prime mover from the generator after the synchronization process and was
left working alone with a few kilowatts to compensate the losses and by means
of its Automatic Voltage Regulator (AVR), the reactive power was controlled
very smoothly without any problem. One can consider the loss we had got and
faced referring to its generator which had got an apparent power of 18.8
MVA and a power of 15 MW if we could understand the difficulty of getting
the spare parts of the gas turbine for its operation and sustainability. The
NEC administration had decided as a consequence matter of the parts non
availability to make the generator as a synchronous condenser by means of
electric drive and NEC tried its best to place tenders so as to do that
particular job, but in vain since as we discovered later that NEC was not
willing to do that work as it was considered as a matter of high cost and that
was on the year 2003 and the whole power station was put out of service and
all its equipments were sold as scarabs and a good opportunity was lost for a
device that could help on the national grid stability and contribute a good
training tool for students of engineering colleges in Sudan.
5.1.2Burri II Power Station:That was the first power station on Sudan and it consisted of different types
of power plant units such as steam and diesel. As the power station was old
and the difficulty of obtaining the spare parts and the original manufacturer's
-
7/27/2019 MSC OF IGs
84/133
-
7/27/2019 MSC OF IGs
85/133
71
generators and that had not been used at the time of power shortage. And
almost most of them were treated similar to NEC policy.
Utilization of old electric machines gets its importance from the comparison
of the new static VAR compensating devices such as capacitors which are
controlled by means of power electronic devices and their bad adverse of
harmonics generation, whereas the old machines could produce a clean
reactive power without any distortion and contribute actively to the steady
state stability of the system.
5.2Potential for Small Hydro Power Schemes:
With reference to the high success of Jebel Aulia Hydro matrix project in
Sudan as a unique scheme in Africa and aiming at best utilization of existing
dams and canals for the production of electric energy with the minimum of
new civil work or additional cost and damage to the environment, experts
from ministry of irrigation ,the Jazeera Scheme board, Elrahad agricultural
project and the previous national electricity corporation NEC decided tomake a feasibility study to study the existing dams and canals for both
Elrahad and Jazeera and Managil schemes.
It is worth mentioning that the expert team was established in the year 2004
with the following engineers:
1- Dr. Ahmed Salih Hussien.. Hydraulic Research Station
Manager (MOI)
2- Eng.Elkarori Elhaj Hamad Dams Directorate Manager
(MOI)
3- Eng. Adam Abbaker .Project Directorate Manager (MOI)
-
7/27/2019 MSC OF IGs
86/133
7
4- Eng.Elzain Abdelrahim..Agricultural Projects Manager (MOI)
5- Eng.Mohamed Oro Salim.. Hydro Power Manager (NEC)
6- Eng.Mudawi Abdelkarim Musa..Hydro Matrix Project Manager
(NEC)
7- Eng.Dafalla ElkabashiEngineering Directorate Manager
(Jazeera Scheme Board)
The expert team started this study from Sennar dam where a similar matrix
turbines of Jebel Aulia could be erected as the dam itself can be divided into
three parts:
1- There are 80 deep sluice gates
2-The gates of Jazeera and Managil canals
3-Downstream canals such as kilo 57and kilo 77
All these parts can be treated similar to Jebel Aulia Hydro matrix turbines
and the estimated powers that would be produced are tabulated as in Data
from Aljazeera, Managil and Elrahad projects shown below.
-
7/27/2019 MSC OF IGs
87/133
72
Fig (5.1) downstream view of Sennar Dam
Fig (5.2) another view of Sennar dam
-
7/27/2019 MSC OF IGs
88/133
73
Fig (5.3) Kilo 0 of Sennar dam
Fig (5.4) Kilo 77 of Jazeera Canal
-
7/27/2019 MSC OF IGs
89/133
74
Fig (5.5) Kilo 57 bridge of Jazeera Canals
-
7/27/2019 MSC OF IGs
90/133
-
7/27/2019 MSC OF IGs
91/133
-
7/27/2019 MSC OF IGs
92/133
77
The data obtained from Elmanagil is shown below on this table
Table (5.1) data from Elmanagil project
It starts from Sennar dam.
It goes in the north direction parallel to Elmanagil canal until kilo 57.
After kilo 57 they are separated and the Jazeera canal continuing to the
north.
-
7/27/2019 MSC OF IGs
93/133
78
Table (5.2) Data from Al jazeera project
STATION GATES(NUM,DIA)MAX.HEAD(M) Max.Discharge In
M3/seconds
ESTIMATED
POWER(MW)
Connection to the
grid
Citiesand
villages
kilo0 from
Sennardam
N=14,5*3M,MANU
AL6.5 218.8 8.5 11 KV Sennar
kilo 77N=4(2P),3*3.75M,M
ANUAL 2.3 150.5 2.1 11KV5villages
kilo 57N=6(2P),3*3.75M,MANUAL
2.5 162.1 2.4 11KV4villages
Beka kilo
108
N=3,3.5*6M,MANU
AL2.3 92.6 1.3 11KV
Many
villages
-
7/27/2019 MSC OF IGs
94/133
-
7/27/2019 MSC OF IGs
95/133
81
Fig (5.10) View No 2 of AbuRakham dam
-
7/27/2019 MSC OF IGs
96/133
8
Fig (5.11) Kilo 22 Bridge on Rahad canal
-
7/27/2019 MSC OF IGs
97/133
-
7/27/2019 MSC OF IGs
98/133
83
Fig (5.13) View no.2 of kilo 36 bridge
-
7/27/2019 MSC OF IGs
99/133
-
7/27/2019 MSC OF IGs
100/133
-
7/27/2019 MSC OF IGs
101/133
-
7/27/2019 MSC OF IGs
102/133
87
-
7/27/2019 MSC OF IGs
103/133
88
CHAPTER VI
CONCLUSIONS AND RECOMMENDATIONS
-
7/27/2019 MSC OF IGs
104/133
89
CHAPTER VI
CONCLUSIONS AND RECOMMENDATIONS
6.1 General
It can be shown that from the views shown below that India is very
famous in this field and has got an excellent experience on the small
hydro power schemes and our country can benefit from it with mutual
cooperation between Sudan and India.
Fig (6.1) typical arrangement of canal fall small hydro power station
-
7/27/2019 MSC OF IGs
105/133
91
Fig (6.2) typical arrangement of small hydro power station
Fig. (6.3) another typical arrangement of small hydro power plant
-
7/27/2019 MSC OF IGs
106/133
9
Fig (6.4) Kalmoni 200 kW SHP project near Guwahati in Assam
6.2The advantages of the experience:
The main advantage in this experience is that they succeeded to generate
hydroelectric power using the small quantity of water and low head.
And the disadvantages when considering the power obtained by means
of synchronous generators is that:
-
7/27/2019 MSC OF IGs
107/133
92
1-They use the conventional type of turbines and this needs more civil
work in the existing dams.
2-The diversion canal increases the civil work.3-The conventional type using of governor system and excitation system
so it increase the capital cost.4-As general it is noticed that the new civil work makes a high cost.
5-Synchronization of small synchronous generators to the grid is very
difficult and risky since the load sharing will not be proper (KW)
between the machines and the grid and the reactive power sharing is
also very difficult (KVAR) and might lead to failure of the small
synchronous generators.
But when we consider the induction generators we can see that the
advantages of the induction generator were: simplicity of control
apparatus, freedom from hunting, no exciter required, no synchronizing
required, low fault currents, low cost, and subsequent general
usefulness in later motor applications and that it is the most suitable
electric machines for such an application.
We are looking forward at future to get use of all our water resources in
our new projects and existing ones and even for the seasonal streams
and canals in all Sudan.
-
7/27/2019 MSC OF IGs
108/133
93
References:
1-Power Engineering International magazine, June 2004.
2-Jebel Aulia hydro matrix power station documents
3-International Energy agent Report (Key issues in developing Renewable
1997)
4-http://grz.g.andritz.com/c/com2011/00/01/24/12429/1/1/2/345644646/hy-
hydromatrix-en.pdf
5-Presentation of small hydro power station done by the joint committee of
NEC and MOI and Jazeera Board.
(http://www.4shared.com/document/bwv2Mzhl/small_hydro.html)
6-Indian experience with small hydro power station
(http://www.mnre.gov.in/prog-smallhydro.htm)
7- from a paper written by OTTO J. M. SMITH with the title (Generator
Rating of Induction Motors) magazine AIEE magazine, volume69, 1950
8-Electric Machinery Fundamentals. By Stephen J.Chapman
http://www.mnre.gov.in/prog-smallhydro.htmhttp://www.mnre.gov.in/prog-smallhydro.htmhttp://www.mnre.gov.in/prog-smallhydro.htm -
7/27/2019 MSC OF IGs
109/133
A
APPENDIX A3
Theory of Poly- phase Induction Machines
The analysis begins with the development of single-phase equivalent circuits.The general form is suggested by the similarity of an induction machine to a
transformer.
The equivalent circuits can be used to study the electromechanical
characteristics of an induction machine as well as the loading presented by the
machine on its supply source.
1. Introduction to Poly phase Induction Machines
An induction machine is one in which alternating current is supplied to the
stator directly and to the rotor by induction or transformer action from the
stator.
The stator winding is excited from a balanced poly phase source and produces
a magnetic field in the air gap rotating at synchronous speed.
The rotor winding may one of two types.
A wound rotor is built with a poly phase winding similar to, and wound with
the same number of poles as, the stator. The rotor terminals are available
external to the motor.
A squirrel-cage rotor has a winding consisting of conductor bars embedded in
slots in the rotor iron and short-circuited at each end buy conducting end
rings. It is the most commonly used type of motor in sizes ranging from
fractional horsepower on up.
The difference between synchronous speed and the rotor speed is commonly
referred to as the slip of the rotor. The fractional slip s is
3Appendix Reference: Electric al Machinery and transformer_ Bhag S.G
-
7/27/2019 MSC OF IGs
110/133
B
s
s
n ns
n
(a .1)
The slip is often expressed in percent.
n : Rotor speed in rpm
s
nsn 1(a .2)
m : Mechanical angular velocity
sm s 1(a .3)
rf : The frequency of induced voltages, the slip frequency
r ef s f(a .4)
A wound-rotor induction machine can be used as a frequency changer.
The rotor currents produce an air-gap flux wave that rotates at synchronous
speed and in synchronism with that produced by the stator currents.
With the rotor revolving in the same direction of rotation as the stator field,
the rotor currents produce a rotating flux wave rotating at ssn with respect to
the rotor in the forward direction.
With respect to the stator, the speed of the flux wave produced by the rotor
currents (with frequency esf ) equals
s s s s1sn n sn n s n (a .5)
Because the stator and rotor fields each rotate synchronously, they are
stationary with respect to each other and produce a steady torque, thusmaintaining rotation of the rotor. Such torque is called an asynchronous
torque.
(a .6)The torque equation2
sr r r
polessin
2 2T F
-
7/27/2019 MSC OF IGs
111/133
C
can be expressed in the form
r rsinT KI (a .7)
rI: The rotor current
r: The angle by which the rotor mmf wave leads the resultant air-gap mmf
wave
Fig.( a.4) shows a typical poly phase squirrel-cage induction motor torque-
speed curve. The factors influencing the shape of this curve can be
appreciated in terms of the torque
equation.
Figure (a .4) typical induction-motor torque-speeds
Curve for constant-voltage, constant-frequency operation.
Under normal running conditions the slip is small: 2 to 10 percent at full load.
The maximum torque is referred to as the breakdown torque.
The slip at which the peak torque occurs is proportional to the rotor
resistance.
2. Currents and Fluxes in Poly phase Induction Machines
-
7/27/2019 MSC OF IGs
112/133
D
2.3 Induction-Motor Equivalent Circuit
Only machines with symmetric poly phase windings exited by balanced poly
phase voltages are considered. It is helpful to think of three-phase machines
as being Y-connected.
Stator equivalent circuit:
11121 jXRIEV (a .8)
1
2
1
1
1
Stator line-to-neutral terminal voltage
Counter emf (line-to-neutral) generated by the resultant air-gap flux
Stator current
Stator effective resistance
Stator leakage reactance
V
E
I
R
X
Figure (a.7) Stator equivalent circuits for a poly phase induction motor.
Rotor equivalent circuit:
2
22
I
EZ (a.9)
2 22s rotor 2s eff eff rotor
2s rotor
E EZ N N Z
I I
(a.10)
2sZ: the slip-frequency leakage impedance of the equivalent rotor
-
7/27/2019 MSC OF IGs
113/133
E
rotorZ: the slip-frequency leakage impedance
2s2s 2 2
2s
EZ R jsX
I (a.11)
2R= Referred rotor resistance
2sR= Referred rotor leakage reactance at slip frequency
2X= Referred rotor leakage reactance at stator frequency
ef
Figure (a.8) Rotor equivalent circuits for a poly phase induction motor at slip
frequency.
22 II s (a.12)
22 sEE s (a.13)
22
EsEs
(a.14)
222
2
2
2
2
jsXRZI
Es
I
Es
s
s (a.15)
-
7/27/2019 MSC OF IGs
114/133
-
7/27/2019 MSC OF IGs
115/133
G
s
sRInP
12
2
2phmech(a.21)
gapmech 1 PsP (a.22)
rotor gapP sP(a.23)
Of the total power delivered across the air gap to the rotor, the fraction 1 s is
converted to mechanical power and the fraction s is dissipated as ohmic loss
in the rotor conductors.
When power aspects are to be emphasized, the equivalent circuit can be
redrawn in the manner of Fig. 6.10.
Figure a.10 Alternative form of equivalent circuit.
Consider the electromechanical torque mechT .
mechmechmech 1 TsTP sm (a.24)
s
sRInPP
T
/22
2ph
s
gap
m
mech
mech
(a.25)
ee
s
f
poles
2
poles
4(a.26)
rotmechshaft PPP (a.27)
-
7/27/2019 MSC OF IGs
116/133
-
7/27/2019 MSC OF IGs
117/133
I
Figure a.13 Induction-motor equivalent circuits simplified by Thevenins
theorem.
m
m
XXjR
jXVV
11
1eq1,(a.29)
1,eq 1,eq 1,eq 1 1 in parallel with mZ R jX R jX jX (a.30)
m
m
XXjR
jXRXjVZ
11
111eq1,
(a.31)
sRjXZ
VI
/
22eq1,
eq,1
2
(a.32)
2
2eq1,
2
2eq1,
2
2
eq1,ph
mech/
/1
XXsRR
sRVnT
s(a.33)
The general shape of the torque-speed or torque-slip curve with motor
connected to a constant-voltage, constant-frequency source is shown in Figs.
a.14 and a.15.
-
7/27/2019 MSC OF IGs
118/133
J
Figure a.14 Induction-machine torque-slip curve showing braking, motor, and
generator regions.
-
7/27/2019 MSC OF IGs
119/133
K
Figure a.15 Computed torque, power, and current curves for the 7.5-kW
motor in Exps a.2 and a.3.
Maximum electromechanical torque will occur at a value of slipmaxTs for
which
2
221,eq 1,eq 2
maxT
RR X X
s (a.34)
2
maxT22
1,eq 1,eq 2
Rs
R X X
(a.35)
2
2eq1,
2
eq1,eq1,
2eq1,
max
5.01
XXRR
VnT
ph
s(a.36)
Figure a.16 Induction-motor torque-slip curves showing effect of changing
rotor-circuit resistance.
(a.5)Parameter Determination from No-Load and Blocked-Rotor Tests
-
7/27/2019 MSC OF IGs
120/133
L
The equivalent-circuit parameters needed for computing the performance of a
poly-phase induction motor under load can be obtained from the results of a
no-load test, a blocked-rotor test, and measurement of the dc resistances of
the stator windings.
a.6.1 No-Load Test:
Like the open-circuit test on a transformer, the no-load test on an induction m
otor gives information with respect to exciting current and no-load losses.
a.6.2 Blocked-Rotor Test:
Like the short-circuit test on a transformer, the blocked-rotor test on an induc
tion motor give information with respect to the leakage impedances.
-
7/27/2019 MSC OF IGs
121/133
M
APPENDIX B
-
7/27/2019 MSC OF IGs
122/133
N
APPENDIX C
SIMPLE KW MULTIPLIER FOR POWER FACTOR CORRECTION
Known Variables: Capacitor Voltage and Capacitor Reactance
KVAR = (2fc)(kv)2
/1000
=(kv)2/1000xc
Known Variables: Capacitor Frequency, Capacitance, and Voltage Rating
KVAR = (2fc)(kv)2
/1000
=(kv)2/1000xc
Reference:
http://www.nepsi.com/powerfactor.htm
-
7/27/2019 MSC OF IGs
123/133
O
APPENDIX D
All the tests and experiments have been done at the faculty of engineering
laboratory (electrical machines lab.)And the following devices and equipments
are used with the following specifications:
Ac induction motor
The motor has got a serial number of 5/15145/290/4/1 and size KKS 3
Power: 2 hp,Speed: 1430rpm, Phases : 3, Frequency: 50 Hz
Voltage:282 v,Current:4.7 Ampere Connection : star
CONT: RatingBs, Insulation class: E, Rotor: 115v current: 8.6 A
The motor is a wound type one where we make it similar to the squirrel cage
one by making short to the windings of the rotor through the slip ring and it is
possible to run it by direct supply of 220 v(three phase supply obtained from
delta side of the lab transformer.)
DC MOTOR
The DC motor is used as a prime mover with the following specifications:
Serial number: 1324-16180, Type: LAP 132-4M
Standard: IEC 34/1 -1969 and now it is IEC 60034/1, Speed: 2900 rpm
Duty: S1, Insulation class: F , Armature voltage: 240 v dc
Armature current: 25.8 A , Excitation voltage: 240 v dc
Excitation current: 0.595 A, IP : 54, IC: 0011 ,IM :1.001
-
7/27/2019 MSC OF IGs
124/133
P
Weight: 145 Kg.
UCTION MOTORDTHE 1 HP IN
This motor is smaller in size and equivalent of one hp and can be operated byeither, 400 v or 230 v of 50 HZ by means of connection of either star or delta;
it has got the following specifications:
The motor name plate is SAER ELETTRO POMPE
Type: HT4-B3-80, Serial number: 1997522, HZ =50
Rated voltage: 240/400 (star/delta), Rated current: 3.6/2.1 A
Speed: 1470 rpm, Power in kW: 0.75, or 1 hp
APPARATUS
The following meters were used for most of the testing and measurements and
all of them were calibrated
a- Power Quality Analyzer (Fluke434)
b- AC/DC multi meter (Fluke 87)c- Clamp meter for ac current measurement
-
7/27/2019 MSC OF IGs
125/133
-
7/27/2019 MSC OF IGs
126/133
R
% The parameters are R1, X1, X2, R2, Xm, Vt, Ns
% Assumed is a three-phase motor
% -----------------------------------------------------
--
Functionsc;
R1 =0.007932;
X1 = 0.1283;
R2 =0.03742;
X2 =0.1283;
Xm =1.6025;
Vt =398.37;
Ns =375;
s = -1:0.003:1; % vector of slip
N = Ns .* (1 - s); % Speed, in RPM
oms = 2*pi*Ns/60; % Synchronous speed in rad/secRr = R2 ./ s; % Rotor resistance
Zr = j*X2 + Rr; % Total rotor impedance
Za = j*Xm.*Zr./(j*Xm + Zr); % Air-gap impedance
Zt = R1 + j*X1 +Za; % Terminal impedance
Ia = Vt ./Zt; % Terminal Current
I2 = Ia .*j*Xm./(Zr + j*Xm); % Rotor Current
Pag = 3 .* abs(I2) .^2 .* Rr; % Air-Gap Power
Pm = Pag .* (1 - s); % Converted Power
Trq = Pag ./oms; % Developed Torque
plot(N, Trq);title('Induction Motor');
ylabel('Torque (N-m)');
xlabel('Speed (RPM)');
gridon;
% -----------------------------------------------------
-% Power Factor-Speed Curve for an Induction Motor
% The machine is 482,8-hp, 690-V, wye-connected, three-
phase, 50-Hz, 16-pole, 375 rpm
% The parameters (referred to the stator) are R1, X1,
X2, R2, Xm,
-
7/27/2019 MSC OF IGs
127/133
-
7/27/2019 MSC OF IGs
128/133
-
7/27/2019 MSC OF IGs
129/133
U
s = -1:0.003:1; % vector of slip
N = Ns .* (1 - s); % Speed, in RPM
oms = 2*pi*Ns/60; % Synchronous speed in rad/sec
Rr = R2 ./ s; % Rotor resistance
Zr = j*X2 + Rr; % Total rotor impedance
Za = j*Xm.*Zr./(j*Xm + Zr); % Air-gap impedance
Zt = R1 + j*X1 +Za; % Terminal impedance
Ia = Vt ./Zt; % Terminal Current
I2 = Ia .*j*Xm./(Zr + j*Xm); % Rotor Current
Pag = 3 .* abs(I2) .^2 .* Rr; % Air-Gap Power
Pm = Pag .* (1 - s); % Converted Power
Trq = Pag ./oms; % Developed Torque
plot(N, Trq);
title('Induction Motor');
ylabel('Torque (N-m)');xlabel('Speed (RPM)');
gridon;
% -----------------------------------------------------
-
% ActivePower-Speed Curve for an Induction Motor
% Assumes the classical model
% This is a single-circuit model
% The parameters are R1, X1, X2, R2, Xm, Vt, Ns% Assumed is a three-phase motor
% -----------------------------------------------------
--
functionapsc;
R1 =6.93;
X1 =2.63;
R2 =3.82;
X2 =2.63;
Xm =104.31;
Vt =230/sqrt(3);Ns =1500;
s = -1:0.003:1; % vector of slip
N = Ns .* (1 - s); % Speed, in RPM
Rr = R2 ./ s; % Rotor resistance
Zr = j*X2 + Rr; % Total rotor impedance
Za = j*Xm.*Zr./(j*Xm + Zr); % Air-gap impedance
-
7/27/2019 MSC OF IGs
130/133
V
Zt = R1 + j*X1 +Za; % Terminal impedance
Ia = Vt ./Zt; % Terminal Current
P =3.*real(Vt.*conj(Ia)); % Total injected active power
plot(N,P);
title('Induction Motor');
ylabel('Active Power (Watts)');
xlabel('Speed (RPM)');
gridon;
%supply parameters
Vin = 230; %voltage
% f = 50 % frequency
% induction motor parameters
Rs = 0.403;
Xs = 0.740;
Rr = 0.511;
Xr = 0.740;
Xm = 12.258;
Ns = 1500;
W = 2*pi*Ns/60;
% 1st case when Slip is constant and Xc varies
% S = -0.02; %-ve slip Generator mode
% Zf = i * Xm * (i * Xr + Rr/S) / ( Rr/S + i * (Xm +
Xr));% Xc = 0:0.1:50 ;%variable series cap.
% Ztotal = Zf + Rs + i * (Xs - Xc);
% I = abs(Vin * Ztotal.^-1);
% ph = angle(Vin * Ztotal.^-1);
% subplot(2,1,1), plot(Xc,I)
% xlabel('Series Capacitance')
% ylabel('Current Amplitude')
% subplot(2,1,2), plot(Xc,ph)
% xlabel('Series Capacitance')
% ylabel('Current phase')Xc = 0.25; % Set here the best value of series cap.
impedance value
S = -1:0.002:1;%variable slip
S(501) = 0.001;% avoid division by zero
Zf = i * Xm * (i * (Xs-Xc)+Rs)/(Rs + i*(Xs+Xm-Xc));
Ztotal = Zf + Rs * S.^-1 + i * Xr;
-
7/27/2019 MSC OF IGs
131/133
W
Vth = Vin * Xm/(Rs + i*(Xm +Xs - Xc));
Ir = abs(Vth * Ztotal .^-1);
T = 3* Rr*(Ir.^2 ./ S)/W ;
plot(S,T)
title('Induction motor Torque/Slip Curve')
xlabel('Slip')
ylabel('Torque')
%supply parameters
Vin = 230; %voltage
% f = 50 % frequency
% induction motor parameters
Rs = 0.403;
Xs = 0.740;
Rr = 0.511;
Xr = 0.740;
Xm = 12.258;
% 1st case when Slip is constant and Xc varies
S = -0.02; %-ve slip Generator mode
Zf = i * Xm * (i * Xr + Rr/S) / ( Rr/S + i * (Xm +
Xr));
Xc = 0:0.1:50 ;%variable series cap.
Ztotal = Zf + Rs + i * (Xs - Xc);
I = abs(Vin * Ztotal.^-1);ph = angle(Vin * Ztotal.^-1);
subplot(2,1,1), plot(Xc,I)
xlabel('Series Capacitance')
ylabel('Current Amplitude')
subplot(2,1,2), plot(Xc,ph)
xlabel('Series Capacitance')
ylabel('Current phase')
% 2nd case when Xc is constant and S varies
Xc = 0.5; % series cap. impedance value
S = -1:0.02:-0.001;%variable slipZfn = i * Xm * (i * Xr + Rr* S.^-1);
Zfd= Rr*S.^-1 + i * (Xm + Xr);
Zf = Zfn ./Zfd;
Ztotal = Zf + Rs + i * (Xs - Xc);
I = abs(Vin * Ztotal.^-1);
ph = angle(Vin * Ztotal.^-1);
-
7/27/2019 MSC OF IGs
132/133
-
7/27/2019 MSC OF IGs
133/133
Pm = Pag .* (1 - s); % Converted Power
Pin = 3.*real(Vt.*conj(Ia)); % Total injected active
power
E = 100.*Pm./Pin; % Efficiency
plot(N,E);
title('Induction Motor');
ylabel('Efficiency (%)');
xlabel('Speed (RPM)');
grid on;