Electrical Protection Relay

Ground Fault Protection  

A Ground Fault Detection and Protection method is typically used to continuously monitor an AC electrical circuit for fault conditions, instantly disconnecting the power in order to minimize loss of life or equipment damage. 

MH offers both DTL and IDMTL ground faults protection relay.

DTL Earth Fault (MH) – EF18
The Earth Fault Relay EF18 is designed to monitor power system and provides a relay operation in the event of an earth fault situation. The EF18 relay incorporates the MTB fault indication system in advanced protection relaying for system abnormalities. This eliminates the need of an auxiliary supply to provide a fault indication, ensuring enhanced safety.

Features

  • Mechanical Trip Button (MTB) fault indication system
  • No requirement for auxiliary power supply for fault indication
  • Safeguard against automatic reset before fault rectification
  • Tamper-proof design for setting protection
  • Type tested for EMC compliance in accordance with IEC 61000
  • High immunity to electrical interference (tested to 2.5GHz)
  • Type tested in accordance with IEC 60255

PDF – EF18 Catalogue

 

Earth Leakage Relay (MH) – EL Series
With the MH Earth Leakage Relay available in either DIN-rail or panel mount type with current/ time selectivity, the MH EL series is a versatile solution for residual current protection for all levels of low voltage installations, from low-voltage lines to power distribution, up to terminal distribution, ensuring a high level of service continuity.
The MH Earth Leakage Relay series are combined with a wide range of zero phase current transformers with diameter sizes from 35mm to 140mm, providing the maximum application flexibility for an effective protection in every point of the system.

Features

  • Manual test button for relay operation checking
  • Realtime monitoring of leakage current [%]
  • Detection of “No-connection” to ZCT (Zero Phase Current Transformer)
  • Tamper proof design for setting protection
  • Type tested for EMC compliance in accordance with IEC 61000
  • High immunity to electrical interference (tested to 2.5GHz)
  • Type tested for operational accuracy in accordance with IEC 60255-1
  • Highest accuracy ZCT (>1,000 ampere-turn transformation)
  • Type tested in accordance with IEC 60044

PDF – EL Series Catalogue

 

IDMTL Earth Fault (MH) – REF052n
Based on digital microprocessor technology, the MH REF052 is designed as a universal earth fault protective relay, integrating selectable time earth fault characteristic curves. With digital processing of input values, the REF052 offers high measuring accuracy and a wide setting range in fine resolution.

Featuring a first-of-its kind, OLED Display (Organic Light Emitting Diode), the ROA207 provides unparalleled clarity and crisp sharpness, alongside the enhanced functions such as communication interfaces, diagnostic features such as fault data recording with time/date stamp.

Features

  • OLED display for superior readability
  • Redesigned menu navigation for intuitive operation
  • Dual source 85-265V AC/DC for auxiliary supply
  • Streamlined 46mm depth with bezel cover
  • Added security against nuisance trip handling
  • Manual test button for relay operation checking
  • No requirement for axially power supply for fault indication
  • Safeguard against automatic reset before fault rectification
  • Curve selection in accordance with ANSI, IAC, IEC, 1.3/10
    • Normally Inverse (NI)
    • Very Inverse (VI)
    • Extremely Inverse (EI)
    • Short Time Inverse (STI)
    • Moderate Inverse (MI)
  • Trip value recording (4-memory)
  • Integrated surge arrester against transient overvoltage
  • High set mode incorporated for instantaneous protection
  • Tamper-proof design for setting protection
  • Serial interface RS485 for Modbus RTU communication (optional)

PDF – REF052n Catalogue

 

Combine IDMTL Overcurrent and Earth Fault (MH) – REA200n

The MH REA200 is designed as a universal, digital microprocessor-based protective relay, integrating both the overcurrent and earth fault protection schemes for definite and inverse time characteristics within one compact unit.

Featuring a first-of-its kind, OLED Display (Organic Light Emitting Diode), the REA200 provides unparalleled clarity and crisp sharpness, alongside the enhanced functions such as communication interfaces, diagnostics features such as fault data recording with time/date stamp.

Features

  • OLED display for superior readability
  • Redesigned menu navigation for intuitive operation
  • Dual source 85-265V AC/DC for auxiliary supply
  • Streamlined 46mm depth with bezel cover
  • Added security against nuisance trip handling
  • Manual test button for relay operation checking
  • No requirement for axially power supply for fault indication
  • Safeguard against automatic reset before fault rectification
  • Curve selection in accordance with ANSI, IAC, IEC, 1.3/10
    • Normally Inverse (NI)
    • Very Inverse (VI)
    • Extremely Inverse (EI)
    • Short Time Inverse (STI)
    • Moderate Inverse (MI)
  • Trip value recording (4-memory)
  • Integrated surge arrester against transient overvoltage
  • High set mode incorporated for instantaneous protection
  • Tamper-proof design for setting protection
  • Serial interface RS485 for Modbus RTU communication (optional)

PDF – REA200n Catalogue

 

Overcurrent Protection  

Overcurrent is a condition which exists on an electrical circuit when the normal load current is exceeded. Any current in excess of the rated current of a conductor or systems may result in risk of fire or shock from insulation damaged from heat generated by overcurrent. 

MH offers both DTL and IDMTL overload protection relay.

DTL Overcurrent (MH) – OA 703
The Overcurrent Relay OA703 is designed to monitor the respective phase current of the power system and provides a relay operation in event of an over current situation. The ROA207 relay incorporates the MTB fault indication system in advanced protection relaying for system abnormalities. This eliminates the need of an auxiliary supply to provide a fault indication, ensuring enhanced safety.

Features

  • Mechanical Trip Button (MTB) fault indication system
  • No requirement for auxiliary power supply for fault indication
  • Safeguard against automatic reset before fault rectification
  • Trip status indication for individual phases
  • Tamper-proof design for setting protection
  • Type tested for EMC compliance in accordance with IEC 61000
  • High immunity to electrical interference (tested to 2.5GHz)
  • Type tested in accordance with IEC 60255

 

IDMTL Overcurrent (MH) – ROA 207n
Based on digital microprocessor technology, the MH ROA207 is designed as a universal overcurrent protective relay, integrating selectable time overcurrent characteristic curves. With digital processing of input values, the ROA207 offers high measuring accuracy and a wide setting range in fine resolution.

Featuring a first-of-its kind, OLED Display (Organic Light Emitting Diode), the ROA207 provides unparalleled clarity and crisp sharpness, alongside the enhanced functions such as communication interfaces, diagnostic features such as fault data recording with time/date stamp.

Features

  • OLED display for superior readability
  • Redesigned menu navigation for intuitive operation
  • Dual source 85-265V AC/DC for auxiliary supply
  • Streamlined 46mm depth with bezel cover
  • Added security against nuisance trip handling
  • Manual test button for relay operation checking
  • No requirement for axially power supply for fault indication
  • Safeguard against automatic reset before fault rectification
  • Curve selection in accordance with ANSI, IAC, IEC, 1.3/10
    • Normally Inverse (NI)
    • Very Inverse (VI)
    • Extremely Inverse (EI)
    • Short Time Inverse (STI)
    • Moderate Inverse (MI)
  • Trip value recording (4-memory)
  • Integrated surge arrester against transient overvoltage
  • High set mode incorporated for instantaneous protection
  • Tamper-proof design for setting protection
  • Serial interface RS485 for Modbus RTU communication (optional)

 

Combine IDMTL Overcurrent and Earth Fault (MH) – REA200n
The MH REA200 is designed as a universal, digital microprocessor-based protective relay, integrating both the overcurrent and earth fault protection schemes for definite and inverse time characteristics within one compact unit.

Featuring a first-of-its kind, OLED Display (Organic Light Emitting Diode), the REA200 provides unparalleled clarity and crisp sharpness, alongside the enhanced functions such as communication interfaces, diagnostics features such as fault data recording with time/date stamp.

Features

  • OLED display for superior readability
  • Redesigned menu navigation for intuitive operation
  • Dual source 85-265V AC/DC for auxiliary supply
  • Streamlined 46mm depth with bezel cover
  • Added security against nuisance trip handling
  • Manual test button for relay operation checking
  • No requirement for axially power supply for fault indication
  • Safeguard against automatic reset before fault rectification
  • Curve selection in accordance with ANSI, IAC, IEC, 1.3/10
    • Normally Inverse (NI)
    • Very Inverse (VI)
    • Extremely Inverse (EI)
    • Short Time Inverse (STI)
    • Moderate Inverse (MI)
  • Trip value recording (4-memory)
  • Integrated surge arrester against transient overvoltage
  • High set mode incorporated for instantaneous protection
  • Tamper-proof design for setting protection
  • Serial interface RS485 for Modbus RTU communication (optional)

 

Other Fault Protection  

There are other protective relays used for electrical control/power system protection which include under/over voltages, reverse power, phases sequence or phase reversal relay and much more. We can offer other protective devices to serve your protection needs.

Over & Under Voltage Relay (MH) – OUV400

The Over & Under Voltage Relay OUV400 is designed to monitor the voltage levels of the power system and provides a relay operation in event of an over or under voltage situation. Incorporating microprocessor based technology, the OUV400 offers high measuring accuracy and a wide adjustment options.

Features

  • Microprocessor based with high accuracy
  • Manual test button for relay operation checking
  • Real time monitoring of voltage levels
  • With over & under voltage mode selection
  • Voltage monitoring ranges from 100-480VAC
  • Trip value recording (4-memory)
  • Integrated surge arrester against transient over voltages