dam instrumentation

7/30/2019 dam instrumentation

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Budhil Hydroelectric Project TS

BHEP/1059/HMW/05-06/Volume 2 Page no- i -

Table of Contents

1 Water level and Measuring system 1

1.1 Water level and Head loss Measuring ,Gate control 1

1.2 Description of Equipment 3



Technical Specifications Electric Control and Measuring Systems

1 ELECTRIC CONTROLS AND MEASURING SYSTEMS

1.1 Water Level and Head-Loss Measuring, Gate Control

1.1.1 General

i) This chapter covers the complete instrumentation & control (I&C) equipment to besupplied and installed by the Contractor.

ii) The contract also covers the control, supervision and position indication of Lot 3

equipment at the intake structure, the spillway gates, desilting gates, draft tube gate

and tail race gate. The intake trash rack and the rack-cleaning machine (RCM) are

automatically supervised by the head loss measurement and the spillway gates are

automatically controlled by the reservoir level measurement.

iii) One common Local Control Panel (LCP) subdivided in particular units for power and

control distribution and interconnections of hydraulic and gate control shall be

supplied by the Contractor and located in the Spillway Gate Control Building as well

as in the Intake Control Building. The panels shall incorporate all electric instruments,

feeders, terminals, control units, indicators and control switches etc. controlling thehydro-mechanical equipment.

iv) The Contractor shall provide the interconnecting wiring work including the

transmitters after the terminal points of the LCP.

v) Even some item not specifically mentioned by these specifications, but required for

the proper and efficient functioning of the equipment, the Contractor shall include its

supply and installation.

1.1.2 Scope and Limits of Supply

i) The main items of instrumentation & control equipment to be supplied and installed

under this section comprise the following:

a) All local control for equipments near installation,

b) Operation facilities in the Spillway Gate Control Building (SGCB),

c) Operation facilities in the Intake Control Building (ICB),

d) One (2) combined water level/ screen head-loss measuring system,

e) One (1) water level measuring system,

f) Four (3) gate position measuring systems for spillway radial gates,

g) Indicators for screen loss and gate positions,

h) Automatic water level control,

i) Automatic control of the flap and the gates,

j) One (1) computing system for calculation the rated discharge of the spillway,

k) Two (2) Air-conditioner, one or each of the SGCB & ICB, to protect the

instruments.

ii) Supply and installation of all apparatus, terminal boxes, protection pipes, sensing

boxes, fixation material etc., necessary to make the distribution services complete and

ready for operation.

iii) The works shall be complete with all necessary auxiliaries such as primary elements

(position transmitters, limit switches, etc.), transducers, cabling, etc., as well as

frames, built-in and embedded parts including all spare parts and special tools

required. All the equipment shall be standard-type of well-known manufacturers.

1.1.3 Design Criteria

i) The spillway operation is based on a strategy balancing the reservoir inflow, availablereservoir capacity and outflow, by checking and comparing measurements taken at

least every 15 minutes.




ii) The specified measuring system shall provide the data (reservoir level, gate position

and spillway discharge) allow determination of the three above-mentioned parameters

by the main computer in the SGCB (Spillway Gate Control Room).

iii) Water level detection shall be by digital water level measurement sensor and shall

consist of float, read switch with resistor, stainless steel pipe work for float, lightningconductor and other necessary accessories. The sensor shall be very sensitive to

transmit the water level considering the fact that these sensors are to work in very

polluted water.

iv) If any of the level sensors provided at any of the points falls defective or gives erratic

readings, the other station shall govern the signals and reservoir control and hence

both the sensing units shall be compatible. Fault detection shall be displayed in the

remote as well as local control panels.

v) The water level signals shall be available at all respective control panels of spillway

radial gates as well as at the power intake.

vi) The signals shall be made available at remote operation panel at the Spillway Gate

Control Building. A facility should also provided for taping the water level signalsalong with gate position indication of the following equipment for further transmission

to Power House Control with alarm signals by way of current signals:

a) Spillway Radial Gates,

b) Intake Gate, Trash Rack, Rack Cleaning Machine.

vii) Design Data:

a) Rated voltage 230V AC, 24 V DC

b) Maximum ambient temperature 50 °C

c) Degree of protection IP 54/IP 67

d) Special treatment Tropicalized

e) Signal output digital BCD Code; min. 4 decadesf) Transmitter Output Signal analogue 4-20 mA (2-wire)

viii) The entire electrical control system shall be of the impulse contact type operating on

24V DC. All terminal strips throughout the system shall be potential free.

ix) All material of the equipment must be suitable for use under tropical conditions.

x) The guarantee period for the control equipment is two (2) years.

xi) Elevation of the reservoir to be considered:

a) Full Supply Level (FSL) 1649.00 m a.s.l.

b) Min. Draw Down Level (MDDL) 1636.60 m a.s.l.

c) Max. Water Level (MWL) 1650.02 m a.s.l.

1.2 Description of Equipment

1.2.1 Power Intake Structure

1.2.1.1 Combined Water Level Measuring and Head-loss Device

i) One (1) set electric water level transmitter, housed in a weatherproof enclosure, shall

be provided at the power intake local control board (LCB).

ii) One (1) water level detector shall be of pressure sensor or hydrostatic pressure

transmitter type and be installed into 100 mm dia. embedded pipe installed u/s of the

trash rack at the extreme right end of the intake wall, connected to the leveltransmitter. The system will be subject to approval of the Engineer-in-Charge.




iii) The water level detector shall be provided in accordance with the following

requirements.

a) Measuring range 23 m

b) Accuracy Less than ±0.1%

c) Elevation of instrument panel 1651.50 m a.s.l.

iv) The water level indicator shall be situated in the LCB.

1.2.1.2 Screen Head-loss Equipment

i) The screen head-loss shall be measured by pressure difference between the upstream

and downstream sides of the intake trash rack. This pressure difference shall be sensed

by comparing reservoir pressure at the upstream side of the trash rack versus pressure

behind the trash rack.

ii) One (2) set of screen head-loss transmitter shall be supplied to detect the head

difference at the intake trash rack, by the signal of the above mentioned water level

sensor and two sensors in the intake of the power waterway.

iii) Two (2) water level detectors shall be of pressure sensor or hydrostatic pressuretransmitter type and are installed into 100 mm dia. embedded pipes provided by the

civil works contractor u/s and d/s of the intake roller gate and connected to the head-

loss transmitter.

iv) The type of equipment to be supplied under the Contract may be differential pressure

sensor or differential pressure transmitter and will be subject to approval of the

Engineer-in-Charge.

a) Measuring range: 6 m

b) Accuracy Less than ±1%,

c) Elevation of sensor installation 1628.00 m a.s.l.

d) Elevation of instrument panel 1651.50 m a.s.l

e) The head-loss system shall introduce:

- At 0.5 m head loss a flashing beacon shall be activated which shall continue

to give visual alarm until the necessary remedial action has been taken

- At 1.0 m head loss a klaxon shall be activated, which can only be muted by

an authorized operator inserting and turning a special key in the control

panel. It must not be possible to withdraw the key in this position.

1.2.1.3 Indicators

i) The indicators shall be situated in the local control panel and consist of:

a) One (1) analogue and one (1) digital type indicator for the head-loss position

shall be mounted on the LCB. The digital position indicator shall display the

value in centimetre. The indicating value of each digital indicator shall be 4digits (00.00-99.99).

b) One (1) digital type indicator for indicating in centimetre the reservoir water

level as transmitted from water level gauge in front of the trash rack shall also

be mounted on the LCB.

c) All necessary instruments, interconnecting wiring, pipe work, housing, cabling,

panel, etc., shall be provided according to the type of equipment proposed to

supply in the Tender and accepted in the Contract.

ii) The Contractor shall provide contacts for the following alarms and indications:

a) AC fault

b) Common Alarm water measuring equipment

c) Trash rack losses height Alarm

d) Head loss indicator 0.0 – 5.0 m




e) The head-loss indicator shall be situated in the LCB and connected to the RCM

control system

f) Position of Intake Roller Gate (stand-by position / stand-by position left)

1.2.1.4 Miscellaneous Items

i) The water level at the reservoir shall be recorded continuously with the latest availablerecording system.

ii) The visual and audible alarms shall be repeated at a remote table mounted in the

Spillway Gate Control Building (SGCB).

iii) One (1) air dehumidifier unit (cooling type with evaporator and compressor) capacity

200 m3 /h without air channels located in the LCB.

iv) All equipment should be protected from lightning surges.

1.2.2 Spillway Structure

1.2.2.1 Water Level Measuring Device

i) One (1) set electric water level transmitter, housed in a weatherproof enclosure, shall

be provided at the Spillway Local Control Panel (LCP).ii) One (1) water level detector shall be of pressure sensor or hydrostatic pressure

transmitter type and be installed into 100 mm dia. embedded pipe installed u/s of the

left guide-wall of the Spillway structure, connected to the level transmitter, will be

subject to approval of the Engineer-in-Charge.

iii) The water level detector shall be provided in accordance with the following

requirements:

a) Measuring range 39 m

b) Actual measuring range 1615.00 m a.s.l. up to 1651.50 m a.s.l.

c) Accuracy Less than ±0.1%

d) Elevation of sensor installation 1615.00 m a.s.l.

e) Elevation of instrument panel 1651.50 m a.s.l.

iv) A digital type indicator for indicating in centimetre the reservoir water level as

transmitted from fore bay water level gauge shall also be mounted on the LCP.

1.2.2.2 Water level Control

i) For automatic control of the water level the Contractor shall supply a system of proven

design. The level variations divided in 1 cm steps shall be transferred to the gate

control automatically at present levels of the reservoir. These levels shall be fixed

during final design. The control of level measuring shall be continuously but at least

five (5) separate adjustable switches should be available for alarm settings.

ii) The level control shall indicate the tendency of raising or lowering of the reservoir

level.iii) The design of the automatic control shall ensure that it is sufficiently fail-safe and

should incorporate features to sound an alarm and indicate all possible malfunctions

and errors. All equipment should be protected from lightning surges.

iv) For automatic gate control and operation system see also the description below.

7.1.1.2 Gate Position Measuring System

i) Electric gate position transmitters (analogous and digital) shall be provided for the

gates. Each position transmitter on the gates shall be housed in a waterproof enclosure

to contain a multi-turn capacitive instrument. All equipment installed at on the gate

body should be protected from lightning surges:

a) Degree of protection IP 68

b) Signal output BCD Code; min. 4 decades

c) Signal analogue 4 – 20 mA

d) Contacts hard gold-plated, 300 µm thick and dry contacts




e) Step size 1 cm

ii) Analogous and digital type indicator for the gate positions shall be mounted on the

LCP The digital position indicator shall display in datum level the vertical distance

between the sill and gate lip to the nearest centimetre. The indicating value of each

digital indicator shall be 4 digits (00.00-99.99).iii) The gate position shall be prominently displayed on a dial type indicator and separate

lamps shall be provided below the indicator to show that the gate has reached the

present position.

iv) The digital type indicator shall reading exact gate vertical opening at 10.0 cm intervals

in 4 digits. Each indicator shall be located and mounted on the LCP.

1.2.2.3 Automatic Gate Control

i) The automatic control of the spillway gates is situated in the LCP and shall work

regarding to the strategy of balancing the water level according final design.

ii) The local control and computing system for the spillway shall be apt to calculate the

actual reservoir water level and gate opening.

iii) The automatic control is defined such as that the gates shall be lifted and loweredsequentially in steps of approx. 0.50 m according to the water level control.

iv) A master controller shall define the required total gate openings. The operation device

shall compare the required value with the total actual opening, found by adding up the

individual opening values, if the deviation of one or more gates from the required

value is large enough, an “Open”- or “Close”- instruction shall be given to the

respective gate(s).

v) Adjustments made manually are to be automatically compensated with the other gates

by the automatic control system. Manually adjusted gates shall, when returned to

automatic mode of operation, be adapted to their normal functioning in the automatic

mode. The automatic system shall work independent of the number of available gates

with the same characteristics. If all gates have been changed over to MANUAL, themaster controller shall be reset so as to permit a smooth switching over to AUTO

operation.

vi) In the event of major changes are required in opening, the gates shall be moved

successively one step each, i.e. after re-setting all gates again agree within the pre-set

margin in size of opening. After all available gates have reached their limit positions; a

corresponding signal shall be given.

vii) In a selection circuit the “open” - instruction shall be transferred to that gate, which at

the time of the comparison controls the smallest opening. Similarly, a “close” -

instruction shall be given to the gate controlling the largest opening. The instruction

shall remain with the selected gate, unless any of the following conditions is met:

a) The required and actual openings agree to the instruction, or

b) The gate had previously reached its limit position, or,

c) The max. permissible deviation (pre-set difference in position between

controlled gate and average of all gates available) has been reached previously.

viii) For the gate selection, only the gates shall be considered, of which the manual

switches are in the 'Automatic 'position, and where no alarm signal has been received.

ix) The gates shall be operable, locally under manual control or automatically from the

LCP.

x) It shall be possible to take any gate out of the automatic mode and operate in the

manual mode. Each opening or closing step shall be initiated by depressing the open

or close push button as appropriate on the LCP.

xi) The system shall be designed to monitor the duration of the instruction. Themonitoring is to prevent, that an instruction is maintained over a period, that is longer

than a pre-selected time, e.g. in the event of a malfunction of a gate selected by the




controller, if the monitoring system is actuated, the particular gate is to be cancelled

from the group of gates available for selection.

xii) The design of the automatic control shall ensure that it is sufficiently fail-save and

should incorporate features to sound an alarm and indicate all possible malfunctions

and proper errors.xiii) Electronic attenuation is to be included to provide against unsteady level signals.

1.2.2.4 Water discharge recording system

i) The local control and computing system for the spillway shall be able to calculate the

actual spillway discharge depending from reservoir water level and gate opening. The

system is to be mounted in the LCP.

ii) These discharge-rating curves shall be also made available from the Contractor in the

ASCI-Code:

a) The discharge rate per gates is to be computed by electronic means. Water

level measurement and measurement of the gate position serve as input

variables,

b) The necessary discharge rating curves shall be agreed with the Engineer-in-Charge. The three discharge rates shall be added and be displayed digitally as

total water discharge rate, which shall also be recorded.

iii) The water discharge by the spillway shall be recorded and indicated continuously with

the latest available recording system in the SGCB.

iv) Provisions shall be made to transmit all controls and indications from each LCP to the

Powerhouse Main Control Board.

v) One (1) air dehumidifier unit (cooling type with evaporator and compressor) capacity

200 m3/ h without air channels located in the SGCB.

vi) All equipment should be protected from lightning surges.

1.2.3 Local control Systemsi) The Contractor shall supply, install within the Intake Control Building, the Spillway

Gate Control Building and the Low-level Gate chamber and commission the electric

control boards, auxiliary equipment and interconnecting cables as specified. Single

line diagrams and layout drawings of the control boards shall be submitted to the

Engineer-in-Charge for approval.

ii) All electrical equipment shall be designed for use in a tropical climate, in order to

avoid operational errors and accidents. The hoisting equipment of all gates shall be

equipped with an electrically operated emergency stop such that all operations of the

motors are stopped on pushing of an emergency stop button.

iii) The electric control panels (LCP, LCB) shall include the required main isolating

breakers for motor, control space heater, current voltmeter and ammeter with selectorswitches, function annunciator block, fault annunciator block, gate position indicators

and all equipment required to provide reliable and fail-safe operation under the

specified service conditions.

iv) Complete wiring of the pump units, hoist / crane electrical equipment and the control

device with all cables shall be included.

v) Additional electrical equipment of the hoists shall comprise the following:

a) A device to transmit the signal that hoist / crane is in progress and operating

failure alarm signals to the control rooms,

b) A cable drum with a junction box for the power supply and electrical control

cables in case of moving hoists and gantry cranes,

c) A waterproof control box including a dehumidifying unit located on the hoist / crane as specified.




vi) The control box shall house the following equipment:

a) A main selector switch (key operated) for the different modes of operation

(local/remote and automatic),

b) Controls comprising push buttons and relays for manual / remote and

automatic as the case may be,c) Position indicators showing the exact position of the gates,

d) Various alarms to indicate the operating faults,

e) A transformer for the control instruments with potential separation.

vii) In addition to all above necessary instrument required for control and measurement is

to be provided by the supplier.

viii) The following instruments but not be limited to, shall be mounted on the control

cabinets:

a) Incoming supply modules case circuit breaker,

b) Source volt meter,

c) Source pilot light,

d) Load ampere meters,

e) Starter for each motor,

f) 230 V 13 A convenience outlet, from own transformer 400/230 V supply,

g) “Gate fully raised” indicating light,

h) “Gate fully lowered” indicating light,

i) “Gate stopped at intermediate position” indicating light,

j) “Raising” indicating light,

k) “Lowering” indicating light,

l) “Gantry crane travelling in left direction” indicating light in case of gantry,

m) “Gantry crane travelling in right direction” indicating light in case of gantry,

n) “Gantry crane stopped” indicating lights,

o) “Trouble conditions” indicating lights,

p) “Multistep speed” controller for travelling equipment,

q) “Light test” push button for travelling equipment,

r) Gate position indicator,

s) Space heater to prevent moisture condensation,

t) Moulded case circuit breakers to protect each motor circuit and other circuits,

u) All other necessary transformers, relays, contractors, switches and

miscellaneous wiring components.ix) The Contractor shall provide the digital transmitters and indications, and terminal

strips via the bus system. These shall include, but not limited to the following:

a) Digital type gate position indications,

b) Digital type water level indication,

c) Digital type discharge value of spillway,

d) Supervisory Items:

- Dry contacts shall be provided for signal transmission to the MCB

- All alarms and indications of each gate

- A.C. fault

- Common Alarm

- O/L Trip




7.1.2 Inspection and Testing

i) Shop Tests:

All equipment shall be checked by the Contractor in order to ascertain its correct functioning

and shall be witnessed by the Engineer-in-Charge.

ii) Site Tests:

Tests to be performed shall include, but not be limited to, the following:

a) Checking of sensitivity of all Equipment,

b) Checking of correct functioning and correct calibration of all Equipment,

c) Automatic operation off the gates shall be tested “dry” by simulating variousreservoir elevations at the level-sensing equipment.

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