ECEN 679 Project 1

Topic 22: Fault Location Using Synchronized

Phasors

Po-Chen Chen Instructor: Dr. M. Kezunovic

Mar. 3, 2014

Reference1) C.-S. Yu, C.-W. Liu, and J.-A Jiang, “A new fault location algorithm for series compensated

lines using synchronized phasor measurements”, IEEE/PES Summer Meeting, vol. 3, pp. 1350 – 1354, Jul. 2000.

2) S. M. Brahma, “New Fault Location Method for a Single Multiterminal Transmission Line Using Synchronized Phasor Measurements,” IEEE Trans. Power Del., vol. 21, no. 3, pp. 1148-1153, Jul. 2006.

3) S. M. Brahma, “Iterative Fault Location Scheme for a Transmission Line Using Synchronized Phasor Measurements,” Int. J. of Emerging Electric Power Syst., vol. 8, no. 6, Nov. 2007.

4) A. T. Johns and S. Jamali, “Accurate fault location technique for power transmission lines,” Proc. Inst. Elect. Eng. C, vol. 137, no. 6, pp. 395-402, Nov. 1990.

5) J.-A. Jiang, et al., “An adaptive PMU based fault detection/location technique for transmission lines-I. Theory and algorithms,” IEEE Trans. Power Del., vol. 15, no. 2, pp. 486-493, Apr. 2000.

Implementation Requirements [1]-[5]

• Synchronized voltage and current phasors (post-fault) from all the terminals of the transmission line are needed.

• DFT to extract phasors from voltage and current samples using PMU.• GPS Common Time Reference using GPS receiver for all terminals.• Communication network.

Possible Errors

• Synchronization Error (GPS time clock).• Phasor Calculation Error.• Modeling and Parameter Error (line asymmetry, distributed parameters,

length of line, the setting errors of data-processing units , etc). • Nonlinear characteristics of CT and CCVT itself

One Phase Example: Fundamental Frequency Model [5]

where and .

Extended for Three-Phase Line • The vector of the three phase voltages and currents, can be written as

• If the line is perfectly transposed, the three phase system can be re-written into positive, negative, and zero sequences. The equations of positive sequence is just like (1) and (2). The equations of negative and zero sequence voltages and currents can also be applied and the number of equations will more than the number of unknowns.

Extended for Three-Phase Line (Cont.)• If the line is NOT perfectly transposed, the the theory of natural modes and

matrix function will be applied.• For two terminal TLs, non-iterative algorithm can be applied [4]. For multi-

terminal TLs, iterative algorithm can be applied [1], [2].

• The method is NOT sensitive to fault type, source impedance variation, or fault resistance. Therefore, the method will not suffer from the estimation errors from these quantities.

• Comparing to algorithms using only one-ended phasor measurements, the computational burden is less. Enough data will create the redundancy (i.e. more equations than unknowns). However, the cost of implementation will be increased.

• Requirements of communication path and synchronization of the phasors will increase the cost of implementation (compared to algorithms using unsynchronized phasors). If the synchronization has error involved, then the fault may not be located properly.

Advantages vs. Disadvantages

Thanks for listening!

Questions?