A DEMO WIDE AREA MONITORING SYSTEM

2011-12-24T08:31:00.001-08:00

A DEMO WIDEAREA MONITORING SYSTEM

Introduction

Grid operations arecomplex in nature and it is becoming more complex when system to bemaintained under strict grid codes and operational efficiencies. Whensystem stretching limits/optimal loading of power system equipments are to be determined dynamically, availability of real time datarepresenting real time network conditions (V, Hz, angle) becomesvery critical. SCADA systems are widely deployed in transmission andgrid operation centers for monitoring of the network parameters,which updates data only at every 5,10 seconds hence data will notrepresent real time state of the network. Usually to representdynamic state of system the informationneed to be acquired in milliseconds.

In AC power system, Powerflows from a point of high voltage angle to a point of low voltageangle. The higher the angle the greater the power flow, hencedetermination of angular displacement and its magnitude (phasors) isimportant. Synchronized measurement of phasor plays an active role indetermining stability of the power system as angular displacement(power angle) determines the stability of the network system.Following events can change voltage angle to increase or decrease

Unscheduled power transfers between source and sinks.
Transmission lines removed (forced or scheduled) from service between source and sink, without adjusting schedules.
Loss of generation in the sink area.
A sudden load throw

General applicationsof synchronized phasors data

Use of real-time PMU data for improved situational awareness
Oscillation monitoring(analysis of sustained oscillations)
Voltage stability Analysis
Supervised Zone 3 protection function
System protection scheme using PMU data
Transfer capacity calculation
CT/CVT calibration

Phasormeasuring unit (PMU)

PMU (Phasor Measurment Unit) derives magnitude and powerangle of the voltage and current with respect to a reference signal,which is generated from a synchronized GPS clock. As the PMUs aresynchronized to single clock system (GPS), the data collected willhave a common time stamp reference to UTC time. The collected datawill be sending to a phasor data concentrator located at controlcentre over IEEE C37.118 communication protocol and updates to masterstation at a rate defined by user and measurement requirement,usually 25,50,10 samples/second.

Wide Area monitoring system for a Load Disptach Center

Kalkitech’s Wide Area monitoring system (WAMs) comprises Phasor Measurement Units(PMUs) of model NI Compact RIO, Phasor Data Concentrator(PDC) of model Kalkitech SYNC4000 and a Historian and visualization system. PMUs are installed at three major locations as indicated by the below figure, in southern region and sends phasor data to the regional load dispatch control centre(RLDC) for real time monitoring and system analysis. The main objective of the pilot is to derive applications using PMU data and understand the capabilities of communication systems available with the transmission operator and its readiness to take up PMU project and also to understand specific features required in the southern sub system operations.

Wide area monitoring applications and phasor data concentrator(PDC) are installed at RLDC control centre and each PMU communicates to control centre over dedicated 64 kbps utility telecom network(E1 network). V.35 modems located at each PMU site provides necessary interface for the PMU to connect to the ULDC network. At control centre PDC time aligns the C37 frames of PMUs and output to the historian and OMS(oscillation monitoring system) application and also provides protocol conversion on ICCP and IEC-879-5-104 for SCADA. The application server has visualization tools and storage application providing displays for phasor monitoring, oscillation monitoring enhancing situational awareness. The information derived from the applications can be used for planning system operation during contingencies.

WAMS user interface

Fig: Oscillation monitoring system and Hz & df/dt plots

Good book to learn about synchrophasors

2009-01-01T15:09:00.000-08:00

The following book is a good one to learn about synchrophasors and applications:

"Synchronized Phasor Measurements and Their Applications" - A.G.Phadke and J.S.Thorpe

- Sushil

Synchrophasor

A DEMO WIDE AREA MONITORING SYSTEM

Good book to learn about synchrophasors