Variations of the RNPP-311 are available upon request. At the customer’s RFP we designed two modifications of the RNPP-311 monitor on the base of the standard RNPP-311 model. Due to microprocessor based technology the device circuitry remained almost unchanged; the modifications were made in the program recorded in the microcontroller’s memory.
TheRNPP-311 (U-f) modification is a two- channel voltage relay designed for usage together with Diesel-generators. The device provides all voltage monitor functions of the standard RNPP-311 and in addition it monitors the mains frequency. The modification is designed to provide load 380V/50Hz de-energization when:
- there are unallowable voltage fluctuations in the mains that last 0.02 sec, the mains voltage peak asymmetry (phase unbalance), phase loss, incorrect phase sequence and phase "coincidence" occur (U channel); .
- the mains frequency exceeds/drops below the set range ( f channel) .
When a voltage is applied to the relay the "Power" LEDs glow. If the voltage is normal (within trip thresholds set for voltage and frequency), thefchannel output contact is energized (the4-5 contacts close) after 0.5 sec delay has expired. TheUchannel, i. e. output for voltage, is energized after 5-6 sec delay has expired (the1-2 contacts close). After that the relay provides continuous voltage and frequency monitoring in the mains.
The1-2contacts open on voltage faults. The green "U" LED of output for voltage goes out.
When voltage parameters return to normal, the load will automatically be energized with 5-6 sec delay.
On voltage faults the "f" output will not trip.
Under abnormal frequency conditions the4-5 contacts open, the green "f" LED goes out. If voltage fault doesn't occur in these circumstances, voltage output "U" will not trip (the 1-2 contacts keep closed position). The frequency output is disabled, the4-5 contacts keep open position. To release the relay one need to remove a voltage from the RNPP-311 and re-apply it again.
The RNPP-311 (Megafon) is a modification of the standard RNPP-311 monitor. This relay is designed to provide 3-phase 380V/50Hz system monitoring and to signalize the phase or phases where normal operating voltage are not present. Unlike the standard RNPP-311 the Megafon doesn't monitor phase sequence, phase "coincidence" and phase unbalance. It has two independent output channels.
The 1st channel signalizes that there is a complete absence of voltage on all three phases in 380V/50Hz lines and/or that the voltages on all phases fall outside the preset Over/Under trip thresholds.
The 2nd channel signalizes that voltage is not present on any one or two phases in 380V/50Hz lines and/or that overvoltage/undervoltage on these phases occurs greater than the trip settings.
1- trip setting control for Umin;
2 - trip setting control for Umax;
3 - green LED of the output for the 1st channel;
4 - green LED of the output for the 2nd channel;
5 - three green LEDs indicating voltage presence on each phase;
6 - input contacts;
7 - output contacts on the 1st channel;
8 - output contacts of the 2nd channel.
The relay is connected in parallel with load through input contacts (L1, L2, L3,N). The relay has two independent outputs: the output for the complete absence of voltage on all three phases (CH 1) with the1-2-3 two-way break-before-make contact group, and the output for absence of voltage on any one/two phases (CH 2) with the4-5-6 two-way break-before-make contact group. When the relay is not alive (a voltage is not applied, the relay is not connected) the2-3 (5-6) contacts are closed and the1-2 (4-5) contacts are open. When the relay is connected in parallel to load, voltage is present in the mains and there is no cause for the relay tripping, the2-3 (5-6) contacts open and the1-2 (4-5) contacts close.
INDICATION
- three green LEDs indicate that voltage exists in the mains. They signalize about the voltages presence on all three phases. When any one or two phases are lost the corresponding LEDs go out;
- green LED of the output for the 1st channel. It glows when the1-2 contacts are closed;
- green LED of the output for the 2nd channel. It glows when the4-5 contacts are closed.
OPERATION
When a voltage is applied to the relay the LEDs "Power" glow. If the voltage is normal, i. e. doesn't fall outside the user-set trip thresholds and is present on all three phases, the output contacts of both channels change their position (the1-2 & 4-5 contacts close, and the2-3 & 5-6contacts open) after 10 sec delay has expired. After that the relay provides a constant monitoring of the voltage value and voltage presence on all three phases.
The 1st channel . When there is the complete absence of voltage and/or voltages fall outside the trip settings on all three phases, both channels trip:
- if voltages fall outside the preset trip thresholds but are still present on all three phases, the4-5 & 1-2 contacts open after the fault (=1.5 sec) delay has expired, green LEDs of the output for the 1st channel (CH1) and of the output for the 2nd channel (CH 2) go out; the "Power" LEDs glow; when voltage parameters return to normal the automatic reset will occur when 60 sec delay has expired;
- if there is the complete absence of voltage on all three phases, the 4-5 & 1-2 contacts open almost immediately, the "Power" LEDs and LEDs of the channel outputs go out; the relay is disconnected; when normal voltage is applied to the relay the channels are energized after 10 sec delay has expired..
The 2nd channel . When voltage is not present on any one or two phases and/or the voltage(-s) fall outside the preset trip settings on these phases the 2nd channel trips. The4- 5 contacts open with fixed (=1.5 sec) delay, green LED "CH2" goes out.
- if one (two) phases fall outside trip thresholds but are not completely lost, all the "Power" LEDs glow;
- according to the complete voltage absence on one (two) phases the corresponding "Power" LEDs go out.
On return to normal voltage parameters the channel will automatically resets when 60 sec delay has expired.
When there are voltage faults on the 2nd channel the 1st channel doesn't trip.
