UTXvD: Overcurrent and earth fault protection

UTXvD is a high-speed, current differential protection relay for HV overhead lines and cables, operating with effectively grounded neutral point.
It provides fast, selective and reliable CB tripping after detection of any kind of PTP (Phase – to – Phase) and PTG (Phase – to – Ground) failure.
The basis for reliable operation of protection device is fast and precise voltages and currents measurements with simultaneous calculation of distance to short-circuit location (option for UTXvD / 8, 8A and 8E).
UTXvD is equipped with digital A/C converters, standardly with network protocols – Ethernet and TCP/IP data transfer and serial interfaces (IEC 870 – 5 – 103 protocol), with fibre optic data transfer possibility. CANBus interface (2 channels) for superior system is optional. Moreover, the device cooperates with Xserver concentrator, which may have DNP3.0 (Distributed Network Protocol version 3) protocol implementation.

UTXvD Hardware Options (available on request)

  • D/4 – four analog signals (3 x CT + 1 x VT) inputs (IL1,IL2,IL3,UE)
  • D/8 – eight analog signals (4 x CT + 4 x VT) inputs (IL1, IL2, IL3, IE, UL1, UL2,UL3, U4) – available with voltage stages; Active/Reactive Power and Energy measurements; Synchrocheck scheme
  • D/8A – eight analog signals (4 x CT + 4 x VT) inputs (IL1, IL2, IL3, IE, UL1, UL2, UL3, U4) – available with voltage stages; Active/Reactive Power and Energy measurements; 1 and 3 phase Auto-reclose and Synchrocheck scheme
  • D/8E – eight analog signals (4 x CT + 4 x VT) inputs (IL1, IL2, IL3, IE, UL1, UL2, UL3, U4) – available with voltage stages; Active/Reactive Power and Energy measurements; 1 and 3 pole Auto-reclose and Synchrocheck scheme. Optionally digital antialiasing active current and voltage filters, for a long-distance EHV lines. This solution is especially useful for unstable waveform suppression, generated at the long-distance EHV lines.

UTXvD characteristics:

  • Multiprocessor, functional decision-making and measuring system, equipped with four groups of protection settings,
  • Galvanically insulated analog and digital inputs and outputs,
  • uniform teleprotection interface, with „weak-infeed” power supply logic and „echo” function,
  • six-zone, rectangular, under-impedance operational characteristics with independent settings both for: R and X (for phase-to-phase faults with distance reduction of RD and XD characteristics) and RE and XE (for earth faults),
  • protective function of line tripping in case of switch-on-to-fault,
  • 1-pole (D/8A, D/8E) and/or 3-pole, 4-step, 6-program autoreclosure for any protective or logic function. AR can be picked up internally or externally. Handling of developing faults. 1-pole and/or 3-pole tripping.;
  • precise Fault Locator (FL) (option for D/8, D/8A, D/8E),
  • LCD bay terminal screen displaying actual (CB, bus and line reclosers, earthing switches) status,
  • possibility to relate each protective function and AR to „link”,
  • automatic of line synchronous switch-on and line tripping blocking in case of power swing occurring (power swing detector) – D/8, D/8A, D/8E,
  • 3-phase, 2-stage overcurrent-time protection: (I>T and I>>T) with various time characteristics,
  • second harmonic phase current compound detector
  • thermal model (two stages, option),
  • 2-stage, directional earth fault protection (IEk1>T and Iek2>T) with rectangular and cosinusoidal angular characteristics and various time characteristics,
  • non-directional earth fault protection with various time characteristics,
  • circuit breaker failure protection (CBFP) – programmable current and time conditions,
  • handling of external emergency tripping request (tripping with fault report and CBFB handling),
  • station signalling functions: BDI, AL, EMT,
  • constant control of breaker circuits continuity,
  • under- and over-voltage stages,
  • signalling of currents and voltages unbalance,
  • functions of cooperation with the circuit breaker, including its remote control,
  • 32 logic functions with programmable modifiers for simple and complex algorithms realization,
  • detailed fault tripping report – events and interference recording (4 (1) voltages, 4 (3) currents and 16 digital channels with 1 ms sampling time) with possibility of recorder internal or external pick up; binary inputs ensure chronological recording of protection device operation and trippings,
  • time synchronization possibility and analog inputs synchronous sampling function,
  • possibility of earth currents values summing, that are switched off by circuit breaker,
  • power measurement, energy meters (four-quadrant) – (D/8, D/8A),
  • OC trip counters and device operation times,
  • graphic display, 11-key keyboard and 16 LEDs (15 freely programmable),
  • measuring values and fault reports display readout and transmission to superior system,
  • device internal systems permanent control,
  • three password-protected authorization levels,
  • possibility of visualization, control and configuration by SAZ 2000 program,
  • possibility of cooperation with Automatic Over Ethernet (AoE) systems and Alice`79 system,
  • possibility of automation realization between stations using TRBus transmission channel.

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