PCS-985 — generator and generator-transformer unit protection terminals
NR PCS-985 is a family of digital protection terminals for generators, generator step-up transformers and station auxiliary transformers of power plants. The protections are used for turbogenerators, gas turbine generators and hydrogenerators, motor-generators of pumped storage plants and generators of nuclear plants with various connection schemes. The terminals work both with conventional CTs and VTs and with electronic ECT/EVT, and are integrated into the plant SCADA.
- Versions
- PCS-985B/AW (generator-transformer unit), 985GI/985GE (generator), 985TI/985TE (auxiliary and unit transformers), 985RE (rotor earth fault), 985U (20 Hz injector), 987R (torsional oscillations)
- Generator types
- turbogenerators, gas turbine generators, hydrogenerators, motor-generators of pumped storage plants, nuclear plant generators
- Stator earth fault protection
- 100 % of the winding with 20 Hz voltage injection (PCS-985U)
- Rotor protection
- against earth faults with external voltage injection (PCS-985RE)
Price, availability and lead time on request. We help with analogue selection, customs clearance and delivery.
Description
The PCS-985B/AW provides comprehensive protection of the generator-transformer unit. The PCS-985GI and PCS-985GE combine the main and backup protections of the generator in one device, together with basic protection of the generator and the excitation transformer, and the PCS-985GE is also suitable for pumped storage plants. The PCS-985GI has up to 56 analogue current and voltage channels, the PCS-985GE up to 28. The PCS-985TI and PCS-985TE protect transformers of any voltage class, typically start-up/standby and auxiliary transformers with several branches, as well as the main transformer. The PCS-985TI additionally provides basic protection of a two-winding main transformer and of one or two auxiliary transformers.
Generator protections include longitudinal and transverse differential protection, including transverse protection by neutral current (87NTG), protection against inter-turn faults, loss of excitation, asynchronous operation, reverse power, stator (49S) and rotor (49E) overload, overexcitation, frequency deviation and inadvertent energisation of the generator (50/27). Stator earth fault protection based on the fundamental zero-sequence voltage (64S1) covers 85–95 % of the winding on the terminal side. The 3rd-harmonic element (64S2) supervises about 25 % of the winding on the neutral side, and together they protect the whole winding. The terminals use frequency tracking, digital filtering and a full-cycle Fourier algorithm. After filtering, the ratio of the zero-sequence voltage to the 3rd harmonic exceeds 100, so the 64S1 protection responds only to the fundamental component.
Specialised devices extend the functionality. The PCS-985U injector supplies a 20 Hz low-frequency voltage to the stator circuit and, together with the PCS-985, forms earth fault protection covering 100 % of the stator winding of a generator operating through a step-up transformer. The PCS-985RE protects the rotor against earth faults by injecting an external voltage. Adaptive active switching makes it possible to monitor rotor insulation even without excitation voltage, with equal sensitivity at any point of the winding, and the device controls the brushes automatically and manually.
The PCS-987R protects the turbine-generator shaft line against subsynchronous torsional oscillations. Such oscillations arise when the plant operates close to series-compensated lines, DC links and large wind farms. All terminals support IEC 61850 and IEC 60870-5-103 and have interfaces for integration into the plant automation system.
Technical specifications
| Versions | PCS-985B/AW (generator-transformer unit), 985GI/985GE (generator), 985TI/985TE (auxiliary and unit transformers), 985RE (rotor earth fault), 985U (20 Hz injector), 987R (torsional oscillations) |
|---|---|
| Generator types | turbogenerators, gas turbine generators, hydrogenerators, motor-generators of pumped storage plants, nuclear plant generators |
| Stator earth fault protection | 100 % of the winding with 20 Hz voltage injection (PCS-985U) |
| Rotor protection | against earth faults with external voltage injection (PCS-985RE) |
| Torsional oscillations / SSO | PCS-987R, protection against subsynchronous torsional oscillations of the shaft |
| Measurement | support for conventional CTs/VTs and electronic ECT/EVT |
| Protocols | IEC 61850, IEC 60870-5-103, interfaces to the plant SCADA |
Request a price and lead time
PCS-985 — generator and generator-transformer unit protection terminals. We reply within one business day.
Or email sales@usk.ua or call 044 339-50-20.
Customs codes
| UKTZED (Ukraine) | 8537 10 98 00 |
|---|---|
| HS, 6 digits | 8537 10 |
| CN (EU) | 8537 10 98 |
| HTSUS (USA) | 8537 10 91 70 |
| China customs tariff | 8537 10 90 90 |
Codes are for reference: the final code is determined at declaration for the specific model.
Questions and answers
For which types of generators is the PCS-985 used?
For turbogenerators, gas turbine generators and hydrogenerators, motor-generators of pumped storage plants and generators of nuclear plants. The PCS-985GE is also suitable for pumped storage stations.
How is 100 % stator winding earth fault protection implemented?
The PCS-985U injector supplies a 20 Hz low-frequency voltage to the stator circuit and, together with the PCS-985 terminal, forms protection of the whole winding. The scheme is intended for generators operating through a step-up transformer.
Does the PCS-985 support electronic current and voltage transformers?
Yes, the terminals work both with conventional CTs and VTs and with electronic ECT/EVT. IEC 61850 and IEC 60870-5-103 are available for communication with the SCADA system.
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