1、 Application scope

The WXH-800A series microcomputer line protection device is mainly used for transmission lines with voltage levels of 220 kV and above. The main protection of WXH-801A is longitudinal direction protection, WXH-802A is longitudinal distance protection, and WXH-803A is fiber optic current differential protection.

2、 Main features

1. The action time of the near end fault of the line is less than 10ms, and the typical metallic fault within the main protection line is less than 30ms.

2. Using virtual braking current to identify TA saturation, the anti zone TA saturation performance reaches 2ms.

3. Adopting a dual digital filtering algorithm to coordinate work effectively ensures the fast action and measurement accuracy of distance protection.

4. Adopting a variable characteristic protection design to achieve the dialectical unity of the "four characteristics" of relay protection.

5. By adopting adaptive oscillation criteria and advanced oscillation recognition functions, the performance of protection during system oscillations has been improved.

6. The multi principle integrated longitudinal protection improves the reliability of protection when the performance of the longitudinal channel changes.

7. Fully supports frame based communication format, enabling precise diagnosis and localization of channel faults.

8. The channel transmission sampling value repair function improves the ability to protect against channel errors.

9. The comprehensive self inspection of AD circuit, CPU plugin, and relay coil has achieved maintenance free hardware of the device.

10. Based on hierarchical, modular, and component-based design, the entire process uses VLD visualization tools to achieve transparency in design, simulation, and testing.

11. The unique "log system" and offline logic simulation function have achieved transparency in accident analysis.

12. Designed with a Windows like graphical user interface, the main wiring diagram is automatically displayed, and the menu is simple and easy to operate.

13. The hardware storage capacity is large, capable of storing up to 100 protection action report records and 50 protection event report records.

14. Open communication design, equipped with RS-485, Ethernet and other communication interfaces, supports IEC60870-5-103 and IEC61850 communication protocols, and has convenient communication point-to-point function.

3、 Protection function

1. Longitudinal direction protection

This protection consists of longitudinal positive sequence fault component direction protection and zero sequence power direction protection, as well as channel interface devices, forming the full line rapid action main protection; The full line speed protection during non full phase operation is achieved by directional components that reflect the power frequency variation of the complete phase. The zero sequence power directional component adopts the full cycle Fourier vector algorithm and is equipped with zero sequence voltage compensation to ensure reliable operation of high resistance faults at the end of the system. The protection is equipped with forward and reverse directional components, and any reverse directional component can lock all forward directional components.

This protection can correctly select the phase and also achieve phase separation transmission signals for phase separation tripping; The phase selection component adaptively selects the phase based on the progress of the fault by inputting sudden variables or steady-state variables.

This protection is equipped with a single (weak) power discrimination element to be applicable to single (weak) power systems.

This protection can be combined with SF-600 transceiver, ZSJ-900 fiber optic digital interface, audio interface device, carrier or other interface devices to form longitudinal protection.

2. Longitudinal distance protection

This protection consists of longitudinal distance (phase to phase, grounding) direction protection and zero sequence power direction protection. The longitudinal distance directional element adopts a fast phasor algorithm to achieve rapid transmission after faults, ensuring that the protection of typical metallic faults along the entire line is less than 30ms. The zero sequence power directional element adopts a full cycle Fourier vector algorithm with zero sequence voltage compensation, enabling reliable operation of high resistance faults at the end of the system.

This protection can correctly select the phase and also achieve phase separation transmission signals for phase separation tripping; The phase selection component adaptively selects the phase based on the progress of the fault by inputting sudden variables or steady-state variables.

This protection is equipped with a single (weak) power discrimination element to be applicable to single (weak) power systems.

This protection can be combined with SF-600 transceiver, ZSJ-900 fiber optic digital interface, audio interface device, carrier or other interface devices to form longitudinal protection.

3. Fiber optic current differential protection

This device is equipped with differential components for various types of faults within the line protection zone, including phase steady-state differential, phase fault component differential, and zero sequence current differential.

The steady-state differential element is equipped with fast zone element and sensitive zone element. The fast zone element adopts short window phasor adaptive algorithm to achieve fast action, so as to protect typical metallic faults within 18ms; The sensitive area adopts the full week Fourier vector algorithm as a supplement to the fast area. The differential fault component is not affected by the load, and has superior performance for high resistance faults and oscillations in the area. The component itself adopts the full cycle Fourier vector algorithm with slight delay to ensure its reliability. Zero sequence current differential serves as a backup delay of 100ms for steady-state differential and fault components, mainly targeting slow climbing high resistance faults.

This protection has a comprehensive capacitor current compensation scheme.

This protection is equipped with remote jump and remote transmission functions.

This protection is equipped with a single (weak) power discrimination element to be applicable to single (weak) power systems.

4. Distance protection

This protection is equipped with three-stage phase to phase distance protection and three-stage grounding distance protection.

The phase to phase distance protection adopts a circular characteristic impedance relay, and the grounding distance protection adopts a polygonal characteristic impedance relay.

5. Zero sequence current (direction) protection

Zero sequence section I, zero sequence section II, zero sequence section III, zero sequence section IV, and zero sequence acceleration section are activated during full phase operation. Zero sequence section I and zero sequence section II cannot be tuned due to zero sequence direction control, while zero sequence section III and zero sequence section IV can be tuned based on direction control.

6. Protection after TV disconnection

After the TV is disconnected, the distance protection is exited, and at the same time, the TV disconnected phase overcurrent and TV disconnected zero sequence overcurrent protection are automatically activated. The zero sequence current direction protection sections I and II are exited. If sections III and IV are not controlled by directional components, the current threshold setting is met and the exit is activated. Otherwise, the zero sequence protection sections III and IV are exited.

7. Automatic reclosing

There are four methods: single weight, triple weight, comprehensive weight, and shutdown.

Meet the calibration requirements of no calibration, synchronous calibration, no voltage calibration, and synchronous calibration of lines with voltage.

The startup method includes protective action startup or switch position mismatch startup

8. Recording waves

The device records the sampling data of 4 cycles before the start of protection and 6 cycles after the start (at 24:00 each week).

9. GPS timing

The timing method adopts the "data stream+pulse" method or IRIG-B method, with a timing accuracy of less than 1ms.

10. Printing function

The device can be configured with a printer to print fixed value and action reports, self check reports, input volume changes, etc;

For devices connected to the substation automation system, printing through the main station does not require the device to be configured with a printer.

11. Network communication

It can directly communicate with microcomputer monitoring or protection management machines, with communication interfaces of RS-485 or Ethernet, and the protocol can adopt IEC60870-5-103 or IEC61850.

12. Self checking function

The device is equipped with comprehensive self checking functions, including self checking of data acquisition circuits, digital circuits, and output circuits, which can self check up to the outlet relay coil. If a malfunction occurs, the LCD display of the device can display the fault information and lock the corresponding protection, while sending an alarm signal.