LineAmps for all lines

INTRODUCTION

LINEAMPS is a complete system of rating overhead power lines, it is easy to use and is

suitable for all regions, operating conditions and all transmission and distribution line

voltages. Program has steady, dynamic, transient ampacity, and weather forecast models

that provides power line ampacity from millisecond to seven days in advance. Weather

data may be input in a number of ways – by user input, in real time from a weather

service, or from the Internet. It is now possible to view all lines in Google map. Program

is operated easily from a control panel comprising a menu system and icons.

LINEAMPS is an integrated line ampacity system with user configurable power line,

conductor and weather station objects offering users easy access to the data stored in

industry standard databases such as Microsoft ACCESS, SQL etc.

LineAmps for all lines

CONSIDERS TRANSMISSION LINE TERRAIN AND WEATHER

Reliable estimates of power line ampacity are only possible when meteorological

conditions and terrain are considered at different sites along the transmission line route.

For this reason LINEAMPS power line object has a number of virtual weather sites

situated along the line.

ECONOMICAL LINE AMPACITY SYSTEM

The system is realized economically because it does not require real time meteorological

data, conductor temperature measurements, conductor sag, conductor tension or any other

real time data from external devices or systems on a continuous basis. The program

generates its own weather data by using key weather information from general purpose

weather forecast data input by the user. It is an economical line ampacity system that runs

in a standard PC in the Windows environment.

LineAmps for all lines

EMS CONNECTION

LINEAMPS can receive actual line current data and contingency plans automatically

from an EMS for the calculation of conductor temperature, and allowable ampacity.

LINEAMPS BENEFITS

♦ Steady, dynamic and transient line ratings

♦ Considers transmission line terrain

♦ Includes overhead lines and underground cables

♦ Forecast hourly ampacity up to seven days in advance

♦ Generates synthetic weather data

♦ Transmission line, conductor and weather station database

♦ Input real time meteorological data automatically from the web

♦ Input real time conductor temperature or line current

♦ View lines with thermal ratings on Google maps

STEADY STATE ANALYSIS

The steady state analysis session window is used for the calculation of conductor

ampacity or temperature during steady state conditions. As shown in Fig.1 conductor may

be selected from a list of different types of conductors or by selecting a line from the list

of transmission lines stored in the database. Current weather conditions of the region are

input automatically from the web. LineAmps provides a separate window as shown in

Fig. 1 and 2 for steady state analysis.

LineAmps for all lines

Fig. 1. Steady State Analysis: Conductor temperature calculation

LineAmps for all lines

Fig. 2. Steady State Analysis: Ampacity calculation

DYNAMIC ANALYSIS

Dynamic analysis is performed to calculate the temperature response of a transmission

line conductor due to a step change in current. A step change in line current may be due

to line energization, short duration overload current during an emergency condition, or

due to high starting current required to operate heavy electrical equipment. During these

conditions higher than normal load current may be allowed for short duration by

considering the heat capacity of conductors. LineAmps provides a separate window as

shown in Fig. 3 for conducting dynamic analysis. As with steady state analysis mentioned

above, conductor and transmission lines data for dynamic analysis is input by simply

LineAmps for all lines

selecting a conductor or a transmission line from the Dynamic Analysis Window and

current weather conditions for the region is input automatically from the web. LineAmps

provides a separate window as shown in Fig. 3, 4 and 5 for dynamic analysis.

Fig. 3. Dynamic Analysis: Overload ampacity calculation

LineAmps for all lines

Fig. 4. Dynamic Analysis: Overload Ampacity calculation and display of conductor

temperature response.

LineAmps for all lines

Fig. 5. Dynamic Analysis: Time to reach maximum temperature

TRANSIENT ANALYSIS

Transient analysis is performed by LINEAMPS to calculate the temperature response of a

conductor due to high fault currents. Short duration fault currents are due to a short-

circuit on the line or a lightning current or any operation that may result in transient over

currents may overheat conductors is easily analyzed by LineAmps. Transient analysis is

generally carried out for durations less than 60 second. Modern protective devices

eliminate faults in much less time and in most cases the fault duration is less than one

second. The transient analysis window is used for evaluating conductor heating due to

LineAmps for all lines

short duration very high line currents. As with steady state and dynamic analysis

mentioned above, conductor and transmission lines data for transient analysis is input by

simply selecting a conductor or a transmission line from the Short Circuit Analysis

Window. Current weather conditions for the region is input automatically from the web.

LineAmps provides a separate window as shown in Fig. 6 for rapidly evaluating

conductor heating as a result of short-circuit currents.

Fig. 6. Transient Analysis: Conductor temperature calculation

LineAmps for all lines

UNDERGROUND CABLE AMPACITY

LINEAMPS provides dynamic ratings of all lines in an electrical network including

overhead lines and underground cables. An example of steady state calculation of

underground cable is presented in Fig. 7.

Fig. 7. Steady State calculation of underground cable temperature and ampacity.

LineAmps for all lines

MODELING UNDERGROUND CABLE CIRCUITS

LineAmps provides easy to use graphical user interface for modeling underground cable

circuits for the calculation of underground cable dynamic ratings. An example of

underground cable circuits in duct bank is shown in Fig. 8. In this example there are two

underground cable circuits sharing the same duct bank. The dynamic line rating

calculations include the effect of mutual heating from adjacent cable circuits in the same

duct.

Fig. 8. Model of underground cable circuits in duct bank

LineAmps for all lines

AUTOMATIC CALCULATIONS

In addition to performing steady, dynamic and short-circuit analysis LineAmps provides

automatic line ampacity calculations at user specified intervals which may vary between

hourly or half hourly calculations of steady state ampacity under normal and emergency

conditions or time to reach critical temperature calculations that are performed more

frequently in the order of seconds.

AUTOMATIC AMPACITY

Steady state ampacity calculations for normal and emergency conditions are updated

automatically every hour or at any other user specified time interval by collecting latest

weather data automatically from the web. An example of automatic steady state ampacity

calculations is shown in Fig. 9, and the latest weather data acquired from the web is

shown in Fig. 10.

LineAmps for all lines

Fig. 9. Automatic Ampacity calculations are performed continuously at user specified

intervals for normal and overload operating conditions. Ampacity limiting site is also

displayed for each line.

LineAmps for all lines

Fig. 10. Weather data from different sites.

TIME TO REACH CRITICAL TEMPERATURE

When transmission lines are operated at high currents it is important for line operators to

know not only the current temperature of the conductor under current weather conditions

but also future evolution of conductor temperature and the time remaining to reach

maximum permissible temperature of the line which we call the critical temperature. In

other words, the operator is interested to know how long it will take for a conductor to

reach maximum temperature at the present level of current passing through the

conductor. LineAmps provides this information by continuously updating present and

future conductor temperature calculations by acquiring latest weather information from

the web or specified weather stations and by obtaining actual level of line current input

from utility scada system.

LineAmps for all lines

Fig. 9. Automatic calculations with display of continuous rating, time to reach maximum

temperature, conductor temperature with graphical display.

LineAmps for all lines

GOOGLE MAPS

Transmission line cartograph in LineAmps has been integrated with Google maps. It is

now possible to view all transmission line elements including weather stations and

transmission line sites on Google map. Line Ampacity, conductor temperature, location

of critical sites and weather data is displayed on the map by clicking on these elements on

the map.

Fig. 10. Transmission lines including sites and weather stations displayed on Google

map.

CONCLUSION

This document describes some of the important features of LineAmps. A demo version of

the program is under development which will allow users to evaluate all of the features

and functions in LineAmps. It is a state of the art dynamic line rating system used by

LineAmps for all lines

many electric power companies in all regions of the world. LineAmps includes dynamic

rating of all transmission and distribution lines in a network including overhead lines and

underground cables. We are continuing to develop LineAmps to include the dynamic

rating of all current carrying elements of a line. We will include transformers, circuit

breakers, isolators, circuit interrupters, bus-bars and all other line elements in the future.

Copyright © 2013. ELECTROTECH ENTERPRISES LLC, Virginia, USA