Synchronized Phasor Measurement Unit (PMU)

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Synchronized Phasor Measurement Unit (PMU)

Electrical Control and Protection II

Assignment

Introduction:

More recent technological advancements in microprocessor relays, combined with GPS receivers for synchronization and accurate time stamping, is providing users advanced relay systems with synchronized measurements, called synchrophasor measurements Synchronized .Wide Area measurements (WAMs) is a relatively modern practice universal in the operation and control of electric power transmission. It consists of making synchronized measurements of phasor quantities of voltages and currents at several points spaced hundreds or thousands of kilometers points. Phasor Measurement Unit (PMU) technology provides phasor information (both magnitude and phase angle) in real time. The importance of data provided by PMUs has been well recognized after a number of major blackouts in many power systems in different parts of the world. PMU is an important component of WAMs.

Synchronized measurements components:

Synchronized measurements of voltages and currents are done by Phasor measurement Units (PMUs). Each PMU has three essential components.

• GPS signal receiver

• Data acquisition module

• Communication module

The GPS signal receiver consists of an aerial and receiver circuits, which detect the 1PPS (pulse per second) and a time tag consisting of the year, day, hour, minute, and second [1].

Synchronizing signal from the GPS satellites. This signal is used to correct for drifts in a local clock oscillator, which keeps the basic time in the PMU. The local clock provides the timing signals to the data acquisition module to sample the voltage and current signals with correct time stamps. These samples are digita...

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...ment and Control System for Increasing Transmission Capacity in Deregulated Energy Markets. Proc. 2002 Power Systems Computation Conference in Sevilla, (2002).

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[3]. Zhang, N & Kezunovic, M. Verifying the Protection System Operation Using An Advanced Fault Analysis Tool Combined with the Event Tree Analysis. Northern American Power Symposium, NAPS 2004 Moscow, Idaho, (August 2004).

[4]. Lin, Y. L; Liu, C. W. & Chen, C. S. (2004). A new PMU-based fault detection/location technique for transmission lines with consideration of arcing fault discrimination— Part I: Theory and algorithms. IEEE Trans. Power Del., Vol. 19, No. 4, (October 2004), pp. 1587–1593.

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