Voltage Protection - ABB Relion 650 Series Product Manual

Transformer protection RET650
Version 2.2
Overcurrent protection with binary release BRPTOC
Overcurrent protection with binary release (BRPTOC) is a
simple, non-directional three-phase overcurrent protection
function with definite time delay. A single step is available
within the function. The current pickup level and definite
time delay can be set independently. It is possible to
release the function operation via a binary signal. If the
binary signal is not connected, the function will
automatically operate in a continuous mode of operation.
Several function instances are available.
From the measured three-phase currents, various types of
measurement modes such as DFT, Peak, and Peak-to-peak
can be selected for the BRPTOC operation.
Peak and Peak-to-Peak measurement mode allow this
function to be used as instantaneous over-current protection
as well. If required by application, short time delay can also
be applied.
BRPTOC can be used for different line and transformer
protection applications. If required, it can also be used to
supervise on-load tap-changer operation.
Pole discordance protection CCPDSC
Circuit breakers and disconnectors can end up with the
phases in different positions (close-open), due to electrical
or mechanical failures. An open phase can cause negative
and zero sequence currents which cause thermal stress on
rotating machines and can cause unwanted operation of
zero sequence or negative sequence current functions.
Normally the own breaker is tripped to correct such a
situation. If the situation persists the surrounding breakers
should be tripped to clear the unsymmetrical load situation.
The Pole discordance protection function (CCPDSC)
operates based on information from auxiliary contacts of the
circuit breaker for the three phases with additional criteria
from unsymmetrical phase currents when required.
The pole discordance function operates based on
information from the circuit breaker logic with additional
criteria from phase selective current unsymmetry.
Directional over/underpower protection GOPPDOP/
GUPPDUP
The directional over-/under-power protection (GOPPDOP/
GUPPDUP) can be used wherever a high/low active,
reactive or apparent power protection or alarming is
required. The functions can alternatively be used to check
the direction of active or reactive power flow in the power
system. There are a number of applications where such
functionality is needed. Some of them are:
• detection of reversed active power flow
• detection of high reactive power flow
Each function has two steps with definite time delay.
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GUID-17DA02BB-B0C0-4AE9-8441-DDA4082A776B v4
M13269-3 v15
SEMOD175421-4 v7
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6. Voltage protection

Two-step undervoltage protection UV2PTUV
Undervoltages can occur in the power system during faults
or abnormal conditions. The two-step undervoltage
protection function (UV2PTUV) can be used to open circuit
breakers to prepare for system restoration at power outages
or as a long-time delayed back-up to the primary protection.
UV2PTUV has two voltage steps, each with inverse or
definite time delay.
It has a high reset ratio to allow settings close to the system
service voltage.
Two step overvoltage protection OV2PTOV
Overvoltages may occur in the power system during
abnormal conditions such as sudden power loss, tap
changer regulating failures, and open line ends on long
lines.
Two step overvoltage protection (OV2PTOV) function can
be used to detect open line ends, normally then combined
with a directional reactive over-power function to supervise
the system voltage. When triggered, the function will cause
an alarm, switch in reactors, or switch out capacitor banks.
OV2PTOV has two voltage steps, where step 1 can be set
as inverse or definite time delayed. Step 2 is always definite
time delayed.
OV2PTOV has a high reset ratio to allow settings close to
system service voltage.
Residual overvoltage protection, two steps
ROV2PTOV
Residual voltages may occur in the power system during
earth faults.
Two step residual overvoltage protection (ROV2PTOV)
function calculates the residual voltage from the three-
phase voltage input transformers or measures it from a
single voltage input transformer fed from an open delta or
neutral point voltage transformer.
A reset delay ensures operation for intermittent earth faults.
ROV2PTOV has two voltage steps, where step 1 can be set
as inverse or definite time delayed. Step 2 is always definite
time delayed.
Overexcitation protection OEXPVPH
When the laminated core of a power transformer or
generator is subjected to a magnetic flux density beyond its
design limits, stray flux will flow into non-laminated
components that are not designed to carry flux. This will
cause eddy currents to flow. These eddy currents can cause
excessive heating and severe damage to insulation and
1MRK 504 172-BEN G
M13789-3 v14
M13798-3 v17
M13808-3 v12
M13319-3 v9
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