BELplus TWNR / TWNZ — differential and complete transformer protection in MV switchgear
BELplus TWNR is a digital differential protection of a feeding transformer in MV switchgear, for two- and three-winding units. The TWNZ version contains the complete set of protections of a transformer bay without a differential element. Both devices are used on 110/MV and MV/MV transformers of substations of distribution networks and industrial enterprises.
- TWNR
- differential protection (stabilized and unstabilized) of two- and three-winding transformers
- TWNZ
- set of protections of a transformer bay (overcurrent, earth fault, etc.)
- Vector groups
- Yd5, Yd11, Yd5d5, Yd11d11, Yy0, etc. — digital matching
- Current inputs
- 6 or 9 phase + 2 I0 channels; 1/5 A, 20 In
Price, availability and lead time on request. We help with analogue selection, customs clearance and delivery.
Description
The terminal works with transformers of typical vector groups Yd5, Yd11, Yd5d5, Yd11d11, Yy0 and others. Interposing current transformers are not needed. The currents of the HV and LV sides are matched digitally, taking into account the transformation ratio of the power transformer and the CT ratios, and the phase shift is corrected by operations on the instantaneous values of the LV side currents. The vector group and clock angle are selected in software, and the phases of the currents can likewise be rotated in software to match the actual CT connection scheme.
The set of inputs depends on the order variant (TWNR2 for a two-winding, TWNR3 for a three-winding transformer). The terminal has HV side current inputs, one or two sets of LV side current inputs, voltage inputs and analog inputs for voltage and two zero-sequence currents, in total 6 or 9 phase currents. The current inputs are universal, 1/5 A, with a range up to 20 In, the voltage inputs are for 100/√3 and 100 V.
TWNR performs stabilized and unstabilized differential protection with blocking by the 2nd and 5th harmonics and elimination of the zero-sequence component of the HV and/or MV sides. The device interacts with the transformer's own protections, each function can be selectively blocked or activated, and the circuit breakers of individual windings are tripped selectively depending on the type of fault. A breaker failure output is provided. Instead of a differential element, the TWNZ version carries the complete set of protections of a transformer bay, including overcurrent and earth fault protections.
Besides protection, the terminal works as a telecontrol controller (telemetering, telesignalling, telecontrol), a disturbance recorder and a slow-process recorder, and also as a master controller for other devices of the substation. The graphic LCD panel is available with a touch screen. 4 setting groups, an event log, graphically programmed logic, two-channel communication with SCADA and a remote engineering channel are available.
The supply according to the order card is 100–270 V DC in the standard version or 24–48 V DC as an option. Supervision of trip and close circuits, hybrid outputs with increased breaking capacity, RS485/RS422, POF/GOF and LAN 100BASE-TX/FX interfaces with PRP and HSR redundancy are provided. The protocols are DNP3.0, IEC 60870-5-103/104 and IEC 61850. The aluminium profile enclosure is flush-mounted or surface-mounted, including in a cabinet or a 19-inch rack.
Technical specifications
| TWNR | differential protection (stabilized and unstabilized) of two- and three-winding transformers |
|---|---|
| TWNZ | set of protections of a transformer bay (overcurrent, earth fault, etc.) |
| Vector groups | Yd5, Yd11, Yd5d5, Yd11d11, Yy0, etc. — digital matching |
| Current inputs | 6 or 9 phase + 2 I0 channels; 1/5 A, 20 In |
| Blocking | by the 2nd and 5th harmonics |
| Setting groups | 4 |
| Supply | 100–270 V DC (standard), 24–48 V DC (option) |
| Protocols | DNP3.0, IEC 60870-5-103/104, IEC 61850, DNP3 over IP; PRP/HSR (option) |
Request a price and lead time
BELplus TWNR / TWNZ — differential and complete transformer protection in MV switchgear. We reply within one business day.
Or email sales@usk.ua or call 044 339-50-20.
Questions and answers
Which transformer vector groups is BELplus TWNR suitable for?
For the typical groups Yd5, Yd11, Yd5d5, Yd11d11, Yy0 and others. The device performs current matching and phase shift correction digitally, without interposing CTs.
How many current inputs does the terminal have?
Depending on the variant, 6 or 9 phase currents plus two zero-sequence current channels. The inputs are universal, 1/5 A, with a range up to 20 In.
How does TWNZ differ from TWNR?
TWNZ has no differential element and contains the complete set of protections of a transformer bay, including overcurrent and earth fault protections. TWNR performs stabilized and unstabilized differential protection with blocking by the 2nd and 5th harmonics.
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