PROTECTA DGYD, OGYD — low-impedance busbar differential protection
The DGYD and OGYD terminals of the PROTECTA line provide low-impedance differential protection of substation busbars in transmission and distribution networks. DGYD is centralised, up to 6 bays per device, OGYD is decentralised, with fibre-optic field units. Used in switchgear of 110–330 kV and above.
- Principle
- low-impedance differential protection with restraint (Kirchhoff's law)
- DGYD
- centralised; up to 6 bays per device, more — three devices (per phase)
- OGYD
- decentralised, field units linked to the central unit over optical fibre
- Switchgear schemes
- single busbar system, up to four busbar systems, ring, one-and-a-half breaker, bus coupler breakers
Price, availability and lead time on request. We help with analogue selection, customs clearance and delivery.
Description
DGYD and OGYD are busbar differential protection terminals of the PROTECTA line for substations of transmission and distribution networks. Both variants operate on the classical principle. In the absence of an internal fault, the sum of the currents flowing into and out of the busbars is zero. If the sum differs from zero, a short circuit on the busbars is detected and a fast trip command is issued to the circuit breakers of the bays of the faulted section. A low-impedance differential protection scheme with restraint, based on Kirchhoff's law, is used.
DGYD is the centralised version. The device receives currents and status signals from all protected busbar bays. If there are few bays (no more than 6), three-phase busbar differential protection is performed by one device. With a larger number of bays the tasks are distributed between three independent devices, each protecting one phase (L1, L2 or L3).
OGYD is the decentralised version. Bay terminals (distance protections, overcurrent protections or special field units) are included in the busbar protection scheme as field devices: they digitise the currents and transmit the required information to the central unit over optical fibre. The central unit performs the calculation and makes the decision, and trip commands are sent back to the field devices also over optical lines. OGYD is designed for busbars with a large number of bays.
The protection has a dynamic busbar model (replica) formed from the disconnector position signals. It is stable during external short circuits, including current transformer saturation, operates in a short time and is selective, so only the bays of the faulted section are tripped while the rest stay in service. Single busbar systems, up to four busbar systems, ring schemes, one-and-a-half breaker schemes and bus coupler breakers are supported, and the system is easy to extend as the switchgear grows. The terminals use the common PROTECTA platform, IEC 61850 Edition 2, a disturbance recorder with up to 32 analogue and 64 binary channels, an event log of more than 10 000 events, and configuration with the EuroCAP program. Applications: open-air and indoor switchgear of 110–330 kV and above, switchgear of power plants and large industrial substations.
Technical specifications
| Principle | low-impedance differential protection with restraint (Kirchhoff's law) |
|---|---|
| DGYD | centralised; up to 6 bays per device, more — three devices (per phase) |
| OGYD | decentralised, field units linked to the central unit over optical fibre |
| Switchgear schemes | single busbar system, up to four busbar systems, ring, one-and-a-half breaker, bus coupler breakers |
| Features | dynamic busbar model based on disconnector positions, stability during current transformer saturation, selective tripping of the section |
| Platform | PROTECTA |
Request a price and lead time
PROTECTA DGYD, OGYD — low-impedance busbar differential protection. We reply within one business day.
Or email sales@usk.ua or call 044 339-50-20.
Questions and answers
How many bays can one DGYD device protect?
Up to 6 bays with one device. With a larger number the tasks are distributed between three devices, one per phase L1, L2 or L3.
How does OGYD differ from DGYD?
OGYD is decentralised. Field devices digitise the currents and transmit them to the central unit over optical fibre, so it is suitable for busbars with a large number of bays.
Which switchgear schemes are supported?
Single busbar system, up to four busbar systems, ring schemes, one-and-a-half breaker scheme and bus coupler breakers. Used in switchgear of 110–330 kV and above.
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