DEIF MVR-200 Medium Voltage Relay: Installation and Wiring Engineering Guide

Range and Frequency: The phase current measurement range is 0.25A RMS, and the frequency measurement range is 6Hz~1800Hz, suitable for power systems of various frequencies (including intermediate frequency and variable frequency applications).

AD conversion: 18 bit ∑ - Δ ADC, sampling 64 points per power frequency cycle to ensure high-precision measurement.

3. Voltage measurement module (VT module)

This module provides 4-channel voltage measurement inputs and supports flexible configuration.

Input characteristics: Each channel has a range of 0~480V RMS (can be directly connected to low-voltage systems or VT secondary side), and a rated voltage range of 100~400V.

Accuracy: ± 0.2% (within the range of 0-240V), with angle measurement accuracy better than ± 0.5 °.

Configuration mode:

3LN+U4: Three phase four wire system (three-phase to ground voltage+zero sequence voltage).

3LL+U4: Three phase three wire system (three wire voltage+zero sequence voltage).

2LL+U3+U4: Two line voltage+calculated value of the third phase+synchronous check input.

Frequency and Sampling: Same as CT module, supports 6-1800Hz, 64 points/cycle sampling.

Troubleshooting tip: The manual provides a detailed troubleshooting table for voltage measurement. When the measurement value is abnormal, the VT ratio setting and measurement mode configuration should be checked first, and then the wiring polarity and phase sequence should be checked. The problem can be quickly located by viewing the "System Voltage Vector Diagram".

4. Arc protection module (option D)

Arc fault is one of the most serious electrical accidents in medium voltage switchgear, which can generate high temperature and high pressure gas within milliseconds, causing serious equipment damage. The arc protection module of MVR-200 is optional (Option D), supporting two types of sensors: optical arc detection and light+pressure composite detection.

Sensor channels: 4 sensor channels, each channel can connect up to 3 arc light sensors in series (daisy chain topology), and a single module can support up to 12 sensors.

Action logic: Supports the combination criterion of "arc light AND overcurrent", which means that the trip will only be triggered when arc light is detected and overcurrent/residual current exceeds the standard, effectively avoiding misoperation caused by external light source interference.

High speed output: The module is equipped with 2 high-speed outputs for quick tripping, ensuring fault removal within 5-10ms.

5. Expand I/O modules

Binary input module (DI8, option B): 8 additional digital inputs, input threshold can be set by software (16~200V), with AC mode anti jitter function.

Binary output module (DO5, option C): 5 additional output relays, including 2 conversion contacts and 3 normally open contacts.

MA Input/Output Module (Option I): 4 mA outputs+1 mA input, used to connect 4-20mA sensors or output analog control signals.

RS-232 communication module (options L/M/N/O): Provides serial fiber optic interface and RS-232 interface, supports IRIG-B time synchronization.

LC100 Ethernet module (option J): 2 100Mbps fiber optic Ethernet ports, supporting HSR/PRP redundancy protocol (IEC 62439-3), meeting the requirements of high reliability substation automation.

Installation and wiring specifications: ensure long-term reliable operation of the system

1. Mechanical installation

MVR-21x (1/4 rack width): Compact in size, 4 devices can be installed side by side in the same 19 inch rack. The size of the panel opening can be found in section 2.2.1 of the manual.

MVR-25x (1/2 rack width): 2 devices can be installed side by side in the same rack, providing more expansion space.

Ventilation requirements: The equipment should be installed on the flat surface of the "Type 1 enclosure" and ensure sufficient heat dissipation space.

2. Protective Grounding (PE)

Use a minimum 2.5mm ² grounding cable to reliably connect the grounding terminal on the back of the equipment to the grounding busbar of the switchgear.

The tightening torque of the grounding terminal is 0.5~0.6 N · m. After the device is powered on, the grounding connection must not be disconnected.

3. Auxiliary power supply wiring

For L-type (low-voltage DC) power supply: It is recommended to install a 4A slow melting fuse on each positive and negative power supply line, and to connect anti reverse diodes (withstand voltage ≥ 100V) in series in the backup power supply circuit.

Power redundancy requirements: For classification society applications, MVR must use reliable dual power supply (main+backup). When the main power supply fails, the backup power supply should be able to immediately take over to ensure uninterrupted protection functions.

Important warning: When MVR loses power, the equipment does not provide any protection function, and all relays will de energize. Therefore, the design of the switchgear must consider backup protection measures in the event of MVR power failure.

4. Voltage measurement wiring

It is recommended to install a 2A slow melting fuse for each voltage measurement circuit, and to be as close as possible to the secondary terminal of the voltage transformer (VT) to protect the measurement circuit and MVR input channel.