Description
A directional/non-directional overcurrent relay presented in an educational format. Supplied with Protection and Relay Test Set , the relay enables investigations into protection and monitoring of generator and transformer schemes, overhead lines, underground cables and backup on high-voltage systems. The relay is housed in a robust enclosure with carrying handle. The module mounts on the desk area of the Protection and Relay Test Set, and connects to it using a multi-core cable and safety leads. This relay is also an optional ancillary for selected products in Power Systems range. The relay module is based on the Micom industrial relay. The lecturer or student sets up different fault circuits on the Protection and Relay Test Set. They then use the keypad and display on the relay module to program it to the settings needed for the tests. They can also use the Micom S1 software (supplied with the Protection and Relay Test Set) and a suitable computer (computer not included) to program the relay module. The relay module is then connected to the fault circuits so tests can be performed. Most tests are performed using single relays. However, there are enough connections on the Protection and Relay Test Set to test two relay modules at the same time. The main functions of the Directional/Non-Directional Overcurrent Relay include: • Three independent stages of directional/nondirectional phase overcurrent . The fi rst stage may be set to any of 12 IDMT curves, the remaining two having a direct time characteristic. • Thermal overload protection• Undercurrent• Negative phase sequence overcurrent • Undervoltage• Overvoltage• Directional/non-directional earth fault• Selectable blocking • Creating fault and disturbance records Connection to the experimental circuit is via current transformers with ratio to suit the inputs of the relay. This provides an effective demonstration of the effect of current and voltage transformer ratio, connection and rating on protective relays.
Learning Outcomes
Investigations into the performance and characteristics of an industrial directional/non-directional overcurrent relay.
Specifications
Dimensions:
• 300 mm x 550 mm x 278 mm
• Packed 0.16 m3
Weight:
• Nett 11 kg
• Packed 31 kg
Current: 1 A (a.c.)
Frequency: 50 or 60 Hz
Accuracy: ±10%
Operating time: Typically 10 ms to 25 ms
Operating Conditions
Operating Environment:
Laboratory Environment
Storage Temprature Range :
–25°C to +55°C (when packed for transport)
Operating Temprature range:
+5°C to +40°C
Operating relative humidity range:
30% to 95% (non-condensing)
