Maloperation of power system protection schemes can result in escalation of a small disturbance to a severe situation in a power system. Events such as power swing, load encroachment, failure of components involved in the protection schemes leads to incorrect operation. This causes unwanted tripping or delay in clearing of faults from the system. This work attempts to use wide-area measurement data to support power system protection decisions in order to avoid maloperations. A combined feature-based decision for relay operation during power swing is developed to derive correct protection decision. Method for supporting relay decisions during stressed conditions such as power swing, voltage instability, and load encroachment by discriminating fault from these events is presented. Indices obtained from WAMS data in a power system are used for identifying malfunction of any element in a protection scheme. Further such informative data improve series compensated and three terminal line protections by applying adaptive settings for distance relays. The WAMS-based techniques enhance protection schemes by making them more reliable and speed up protection for power networks.

Chapter Contents:

• 3.1 Introduction
• 3.1.1 WAMS architecture
• 3.1.2 WAMS communication
• 3.1.2.1 Communication delay causes
• 3.2 Improved network protection during stressed conditions
• 3.2.1 Protection support during power swing
• 3.2.1.1 Wide-area severity indices
• 3.2.1.2 Simulated test system
• 3.2.1.3 The method
• 3.2.1.4 Case study for eastern India test system: out-of-step condition
• 3.2.2 Improved zone 3 operation
• 3.2.2.1 Synchrophasor placement
• 3.2.2.2 The method
• 3.2.2.3 Case study
• 3.3 Online identification of protection element failure
• 3.3.1 Faulted line identification
• 3.3.2 Component failure indices
• 3.3.3 Signal communication
• 3.3.4 The method
• 3.3.5 Case study: relay underreaching
• 3.4 Adaptive protection
• 3.4.1 Series compensated line
• 3.4.1.1 The adaptive method
• 3.4.1.2 Result
• 3.4.2 Three terminal line
• 3.4.2.1 The adaptive method
• 3.4.2.2 Results
• 3.5 Conclusion
• Nomenclature
• References

Inspec keywords: relay protection; power system reliability; power system faults; power system measurement; power system protection

Other keywords: maloperation avoidance; distance relay; unwanted tripping; malfunction identification; power swing; power system protection schem; power system disturbance; wide area measurement-based power network protection; three terminal line protection; power system fault; combined feature-based decision; relay operation; wide area measurement

Subjects: Power system protection; Power system measurement and metering; Reliability