PCS-978 / PCS-9671 — power transformer and reactor protection terminals
The NR PCS-978 / PCS-9671 series covers protection terminals for power transformers, autotransformers and shunt reactors of all voltage classes. The flagship PCS-978 provides the full protection and control scheme for multi-winding transformers, while the compact PCS-9671 and PCS-9671S are designed for networks of 110 kV and below. The terminals are used at grid company substations, on generator step-up transformers at power plants and in industry.
- Versions
- PCS-978, PCS-978S for full protection; PCS-9671, PCS-9671S compact (up to 110 kV); PCS-974 gas/process protection relay
- Protected objects
- two- and multi-winding transformers, autotransformers, shunt reactors
- Analogue inputs
- up to 36 current/voltage inputs, up to 6 CT groups in the differential protection (PCS-978)
- Connection groups
- 288 variants (PCS-978)
Price, availability and lead time on request. We help with analogue selection, customs clearance and delivery.
Description
The PCS-978 and the new-generation PCS-978S have up to 36 analogue current and voltage inputs. This is enough for transformers in one-and-a-half breaker schemes and polygons: up to 6 groups of current transformers can be included in the differential protection, and 288 winding connection groups are supported. The compensation angle is set freely, and any side can be selected as the base. The PCS-978S is designed for two- and three-winding transformers and autotransformers of any voltage class, is configured in PCS-Studio and supports PRP/HSR redundancy.
The compact PCS-9671 is intended for two-winding transformers and is also used as differential protection of a reactor or of a busbar connection in a one-and-a-half breaker scheme. It provides restrained (87T) and unrestrained (87UT) differential protection and zero-sequence winding differential protection (64REF). The PCS-9671S works with up to three measurement points, i.e. with two- and three-winding transformers, autotransformers and reactors of 110 kV and below. The device is built on a 32-bit dual-core processor with a 16-bit ADC; the front panel has a 240×128 pixel display, 9 buttons and 20 LEDs.
The main functions include restrained and unrestrained transformer differential protection, REF protection, and blocking on magnetising inrush and overexcitation. Inrush is recognised by two methods, by waveform distortion and by the 2nd and 3rd harmonics, with adaptive and cross-phase blocking. The same harmonics detect steady-state and transient CT saturation, and the 3rd and 5th harmonics are included in the V/Hz calculation for overexcitation protection. Supervision of CT circuit breaks in the differential protection prevents false operation. Backup protections include directional and non-directional overcurrent protection of phase, zero-sequence and negative-sequence currents, distance protection, thermal overload protection, voltage and frequency protection, and breaker failure protection.
For process (non-electrical) protections the PCS-974 relay is used, with sixteen binary inputs of increased operating threshold. A gas relay, oil and winding temperature sensors and other mechanical devices are connected to it for alarm and tripping, and the high operating threshold reduces the risk of false operation caused by electromagnetic interference. All terminals support IEC 61850 on the station bus and process bus (MMS, GOOSE, SV), DNP3.0 and IEC 60870-5-103, and time synchronisation via IRIG-B, SNTP, PPS and IEEE 1588. They have event and COMTRADE oscillogram recorders, self-diagnostics and a front RJ45 port for commissioning.
Technical specifications
| Versions | PCS-978, PCS-978S for full protection; PCS-9671, PCS-9671S compact (up to 110 kV); PCS-974 gas/process protection relay |
|---|---|
| Protected objects | two- and multi-winding transformers, autotransformers, shunt reactors |
| Analogue inputs | up to 36 current/voltage inputs, up to 6 CT groups in the differential protection (PCS-978) |
| Connection groups | 288 variants (PCS-978) |
| Main functions | differential protection (87T), zero-sequence differential protection (REF, 64REF), backup overcurrent and distance protections |
| Process protection | PCS-974: 16 binary inputs with a high operating threshold for gas relay and temperature indicators |
| Protocols | IEC 61850 (MMS, GOOSE, SV), DNP3.0, IEC 60870-5-103 |
Request a price and lead time
PCS-978 / PCS-9671 — power transformer and reactor 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
How many current transformer groups can be connected to the PCS-978 differential protection?
Up to 6 CT groups with a total of up to 36 analogue inputs. The terminal supports 288 winding connection groups and is used in one-and-a-half breaker schemes and polygons.
Which terminal should be chosen for a 110 kV transformer with two or three measurement points?
The compact PCS-9671S is designed for such installations. It protects two- and three-winding transformers, autotransformers and reactors of 110 kV and below.
How to connect the gas relay and the transformer temperature sensors?
They are connected to the PCS-974 process protection relay with 16 binary inputs. The high operating threshold of the inputs reduces the risk of false operation caused by electromagnetic interference.
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