Comprehensive three-phase differential relay testing
Advanced Differential is a set of test modules which form a complete testing solution for differential schemes. It is particularly suitable for transformer differential schemes with up to three windings and up to nine currents to be injected.
This test solution provides:
- Testing with all fault types (L-N, L-L, L-L-L)
- Shot tests at pre-defined test points or search tests
- All shots synchronizable to GPS or IRIG-B for end-to-end testing (e.g. line differential protection)
- Evaluation and assessment of results against nominal characteristics and tolerances
- Report generation including graphical representation of the results in the characteristic diagrams
- No blocking of voltage related functions required (important for testing of multifunctional relays)
Details of the four test modules in Advanced Differential
This module simulates through-faults to verify that the protection is stable for faults outside the protected zone.
Diff Operating Characteristic
Diff Operating Characteristic tests the operation of the protection for faults inside the protected zone.
Diff Trip Time Characteristic
This module tests the dependency of the trip time from the magnitude of the differential current.
Diff Harmonic Restraint
Diff Harmonic Restraint tests the inrush and CT saturation blocking function of a differential relay. The test points are defined in the harmonic restraint characteristic diagram, where the differential current is drawn over the harmonic content of the test current.