Protection Relays MELPRO-A Series
Product Features
Protection relay for digital type high voltage power system maintain high stability and stable characteristics. MELPRO-A is numerical protection relay with accurate and stable characterstics for high voltage power systems.
Since the new model is compatible with the existing one, it is suitable for design upgrade and replacement.
Design
Support various protection scheme
Three stage OCR elements are provided. 3rd stage is added to the instantaneous function of OCR. 3rd stage OCR can operate with a current (4 steps of 20 to 80%) less than the instantaneous element, making it easy to coordinate the protection system of distribution substations. Minimum setting value of Vo of DGR is expanded to 2%, with enables higher sensitivity for ground fault.
Increase of relays connected with ZVT
The maximum number of DGR or OVGR that can be directly connected with the zero-phase voltage detector (ZVT:MPD-3) is increased to 20.
※When configured with the MELPRO-A only.
Compliant with standards
In recent years, the standards for protection relays have been revised to take protection characteristics of the numerical relay. MELPRO-A is compliant with the latest standard of JEC and JIS.
Easy Renewal
The panel cutout is the same as the existing A series. It offers easy replacement without panel modification. Moreover, the protection and setting of the new one is upper compatible.
Operation
High visibility and operability design
By improving the knob structure of the switch, the operability and visibility is improved. Moreover, the characters on the front panel based on UD (Universal Design) are large and easy to read.
LED display of setting values
Equipped with a function that preferentially displays the changed value of the setting on the LED for about 3 seconds when the setting is changed. It is easy to check the set value even during work such as unit tests.
Maintenance
Various functions to notify the abnormality of the relay
- 1.Equipped with a "Constant monitoring function" that constantly checks the input, power supply, and CPU circuits. Even if the protective relays fail, This function supports to grasp the situation quickly.
- 2.Equipped with a "Frequency error detection function", that displays a warning when the setting frequency and the input frequency are differrent. This function supports to prevent setting mistakes.
※Only for three models of OCR, UVR and OVR.
Equipped with a Fault record function
All models are equipped with a function to record and display the fault value when the relay tripped. This function supports to grasp the fault condition.
Saving of maintenance work
For the draw out type (RD type) model, the inside of the relay can be pulled out with the wiring connected to the case, which saves labor during maintenance work.