Electrical Protection Relays

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.

 

N Series

DTL Earth Fault (MH) – EF 18
The Earth Fault Relay EF 18 is designed to monitor power system and provides a relay operation in the event of an earth fault situation. The EF 18 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

MH EF 18 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

MH EL Series Catalogue

 

IDMTL Earth Fault (MH) – REF 052n
Based on digital microprocessor technology, the MH REF 052 is designed as a universal earth fault protective relay, integrating selectable time earth fault characteristic curves. With digital processing of input values, the REF 052 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 ROA 207 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)

MH REF 052n Catalogue

 

Combine IDMTL Overcurrent and Earth Fault (MH) – REA 200n

The MH REA 200 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 REA 200 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)

MH REA 200n Catalogue

 

E Series

DTL Earth Fault (MH) – EF 18e

A similar, but simplified version of MH DTL earth fault relay EF 18, the EF 18e provides elementary protection functions excluding the MTB fault indication system.

Features

  • Tamper-proof design for setting protection 
  • Type tested* for EMC compliance in acc. With IEC 61000
  • High immunity to electrical interference (tested to 2.5GHz)
  • Type tested in acc. With IEC 60255*

MH EF 18e Catalogue Rev.1

MH EF 18e Operation and Installation Guide V1

 

DTL Earth Fault (MH) – REF 18e

A similar, but simplified version of MH DTL earth fault relay EF 18, the REF 18e provides elementary protection functions excluding the MTB fault indication system.

Features

  • Tamper-proof design for setting protection 
  • Type tested* for EMC compliance in acc. With IEC 61000
  • High immunity to electrical interference (tested to 2.5GHz)
  • Type tested in acc. With IEC 60255*

MH REF 18e Catalogue Rev.1

MH REF 18e Operation and Installation Guide V1

 

IDMTL Earth Fault (MH) – REF 052e
A similar, but simplified version of MH IDMTL earth fault relay REF 052, the REF 052e provides elementary protection functions excluding the MTB fault indication system.

Features

  • Designed with LED display
  • Added security against nuisance trip handling
  • Manual test button for relay operation checking
  • 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 overvoltages
  • High set mode is incorporate for instantaneous protection
  • Tamper-proof design for settings protection
  • Serial interface RS485 for Modbus RTU communication (Optional)

MH REF 052e Catalogue Rev.1

MH REF 052e Operation and Installation Guide V1

 

Combine IDMTL Overcurrent and Earth Fault (MH) – REA 200e

A similar, but simplified version of MH combined IDMTL overcurrent and earth fault relay REA 200, the REA 200e provides elementary protection functions excluding the MTB fault indication system.

Features

  • Designed with LED display
  • Added security against nuisance trip handling
  • Manual test button for relay operation checking
  • 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 overvoltages
  • High set mode is incorporate for instantaneous protection
  • Tamper-proof design for settings protection
  • Serial interface RS485 for Modbus RTU communication (Optional)

MH REA 200e Catalogue Rev.1

MH REA 200e Operation and Installation Guide V1

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.

N Series

DTL Overcurrent (MH) – OA 703
The Overcurrent Relay OA 703 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 ROA 207 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

MH OA 703 Catalogue

 

IDMTL Overcurrent (MH) – ROA 207n
Based on digital microprocessor technology, the MH ROA 207 is designed as a universal overcurrent protective relay, integrating selectable time overcurrent characteristic curves. With digital processing of input values, the ROA 207 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 ROA 207 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)

MH ROA 207n Catalogue

 

Combine IDMTL Overcurrent and Earth Fault (MH) – REA 200n
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 REA 200 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)

MH REA 200n Catalogue

 

E Series

DTL Overcurrent (MH) – OA 703e
A similar, but simplified version of MH DTL overcurrent relay OA 703, the OA 703e provides elementary protection functions excluding the MTB fault indication system.

Features

  • Trip status indication for individual phases
  • Tamper-proof design for setting protection
  • Type tested* for EMC compliance in acc. With IEC 61000
  • High immunity to electrical interference (tested to 2.5GHz)
  • Type tested in acc. With IEC 60255*

MH OA 703e Catalogue Rev.1

MH OA 703e Operation and Installation Guide V1

 

IDMTL Overcurrent (MH) – ROA 207e

A similar, but simplified version of MH IDMTL overcurrent relay ROA 207, the ROA 207e provides elementary protection functions excluding the MTB fault indication system.

Features

  • Designed with LED display
  • Added security against nuisance trip handling
  • Manual test button for relay operation checking
  • 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 overvoltages
  • High set mode is incorporate for instantaneous protection
  • Tamper-proof design for settings protection
  • Serial interface RS485 for Modbus RTU communication (Optional)

MH ROA 207e Catalogue Rev.1

MH ROA 207e Operation and Installation Guide V1

 

Combine IDMTL Overcurrent and Earth Fault (MH) – REA 200e

A similar, but simplified version of MH combined IDMTL overcurrent and earth fault relay REA 200, the REA 200e provides elementary protection functions excluding the MTB fault indication system.

Features

  • Designed with LED display
  • Added security against nuisance trip handling
  • Manual test button for relay operation checking
  • 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 overvoltages
  • High set mode is incorporate for instantaneous protection
  • Tamper-proof design for settings protection
  • Serial interface RS485 for Modbus RTU communication (Optional)

MH REA 200e Catalogue Rev.1

MH REA 200e Operation and Installation Guide V1

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) – OUV 400

The Over & Under Voltage Relay OUV 400 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 OUV 400 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

MH OUV 400 Catalogue