This chapter has investigated the influence of the fault arc nonlinearity and the input device error on the accuracy of digital fault locators. A time domain simulation model of the digital fault locator was represented using the MODELS language in the ATP-EMTP. Various types of faults were simulated with constant and nonlinear fault arc resistances. The simulation results have shown that the impedance relay type method is influenced by the nonlinear characteristics of the fault arc, while the current diversion ratio method is not. A sensitivity analysis of the locating error with respect to the model parameters of the nonlinear arc resistance was performed for the impedance relay type method. It has been observed that the greater the degree of nonlinearity, the greater the location error. CT errors were considered, and it was observed that the CT saturation error does not last long enough to affect the fault location result and thus can be ignored.

Chapter Contents:

• 10.1 Introduction
• 10.2 Fault locator
• 10.2.1 Fault locator algorithm
• 10.2.2 Fault locator model description using MODELS
• 10.2.3 Study on influence of fault arc characteristics
• 10.2.4 Study on influence of errors in input devices
• 10.3 High-speed switchgear
• 10.3.1 Modeling methods
• 10.3.2 Comparative study with measurement
• 10.3.3 Influence of voltage sag magnitude
• 10.4 Conclusions
• References

Inspec keywords: sensitivity analysis; power engineering computing; EMTP; fault location; switchgear; fault currents

Other keywords: diversion ratio method; nonlinear arc resistance; digital fault locators; impedance relay type method; sensitivity analysis; nonlinear fault arc resistances; MODELS language; protective devices; ATP-EMTP; high-speed switchgear; time domain simulation model

Subjects: Power engineering computing; Inspection and quality control; Switchgear