Power, voltage and frequency relay
NPW800 performs the measurement of the apparent (S), active (P) and reactive (Q) power of 3 or 4 wire electrical networks. The monitoring of the energy flow direction is completed by the management of power factor, tangent φ and by the supervision of network voltage and frequency.
As well as the usual protection functions, NP800 relays provide monitoring, measurement and recording of the electrical quantities of the network.
The relays can be set locally, using either the keypad and display or the RS232 port, or remotely using the RS485 port.
Setting, reading, measurement and recording are all available locally or remotely.
CONTROL AND PROTECTION FUNCTIONS
- Maximum of active power with 2 thresholds [32P]
- Minimum of active power with 2 thresholds [37P]
- Max of reactive power with 2 thresholds [32Q]
- Min of reactive power with 2 thresholds [37Q]
- Overvoltage with 3 thresholds 
- Undervoltage with 3 thresholds 
- Overfrequency with 4 thresholds [81O]
- Underfrequency with 4 thresholds [81U]
- Max of zero sequence voltage with 2 thresholds [59N]
- Management of the network power factor with 2 thresholds 
- Management of the network tangent φ with 2 thresholds [Q/P]
- Max of Active ΣP and reactive ΣQ integrated power with 2 thresholds
- Latching of the output contacts 
- Trip circuit supervision of the breaker [74TC]
- Breaker failure [BF]
- Configuration and parameter setting by local MMI or off-line / on-line PC
- Measurement of electrical quantities:
– Instantaneous and integrated values of phase currents and S, P, Q power
– Values, according to the wiring, phase to phase or phase to neutral and the residual voltage
– Power factor, Cosφ
– Instantaneous value of tangent φ
- 2 setting groups, locally or remotely selectable by digital input or by the communication channel
- Self-diagnosis: Memories, output relays, A/D converters, auxiliary supply, cycles of execution of software, hardware failure
- 7+1 assignable output units / 8 assignable digital inputs
- Event recording: 250 locally recorded events, 200 saved in case of loss of auxiliary supply
- Disturbance recording according to Comtrade® format: storage of 4 recordings of 52 periods
- Optional Communication by Modbus® RS 485 or Ethernet by Modbus/TCP