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10
NV021 - Manual - 08 - 2012
GENERAL
2 G E N E R A L
Preface
The relay type NV021 can be typically used in HV, MV and LV distribution systems, on transformers
or for electrical machines.
It can be used for system decoupling, load shedding and loss of main (islanding) protection.
In addition to the main protection element, the breaker failure (BF) , Trip Circuit Supervision (TCS) and
programmable logic (PLC) are also provided are also provided
Setting, programming and reading operations must be effected by means of Personal Computer with
ThySetter software or by means of remote communication interface (RS485 bus and Ethernet net-
work); all operations must be performed through MMI if enabled.
According to the hardware confi gurations, the NV021 protection relay can be shipped in various
case styles depending on the required mounting options:
Flush.
Projecting mounting.
Rack.
With separate operator panel.
Other options are:
Auxiliary power supply operating range.
Communication protocols.
Input circuits for direct connection
Three voltages (line-to-line) with nominal voltages programmable in the range 200...520 V (
U
R
= 400V)
are available.
—
•
•
•
•
•
•
—
74TCS
BF
27
27V1
81O
81R
81U
59V2
59
DDI
59Uavg
PROTECTION RELAY
NV021
- Protective & control functions
27 Phase
undervoltage
27V1
Positive sequence undervoltage
59 Phase
overvoltage
59V2 Negative
sequence
overvoltage
59Uavg Average
overvoltage
81O Overfrequency
81U Underfrequency
81R
Frequency rate of change
BF
Circuit breaker failure
74TCS
Trip circuit supervision
ARF Automatic
reclosure
(optional for pv plants)
74TCS
BF
27
27V1
81O
81R
81U
59V2
59
DDI
59Uavg
PROTECTION RELAY
NV021
- Protective & control functions
27 Phase
undervoltage
27V1
Positive sequence undervoltage
59 Phase
overvoltage
59V2 Negative
sequence
overvoltage
59Uavg Average
overvoltage
81O Overfrequency
81U Underfrequency
81R
Frequency rate of change
BF
Circuit breaker failure
74TCS
Trip circuit supervision
ARF Automatic
reclosure
(optional for pv plants)