The fuse failure supervision function basically has three different
detection methods, negative sequence and zero sequence
based detection and an additional delta voltage and delta
current detection.
The negative sequence detection is recommended for IEDs
used in isolated or high-impedance earthed networks. It is
based on the negative-sequence measuring quantities, a high
value of negative sequence voltage 3U
2
without the presence of
the negative-sequence current 3I
2
.
The zero sequence detection is recommended for IEDs used in
directly or low impedance earthed networks. It is based on the
zero sequence measuring quantities, a high value of zero
sequence voltage 3U
0
without the presence of the zero
sequence current 3I
0
.
For better adaptation to system requirements, an operation
mode setting has been introduced which makes it possible to
select the operating conditions for negative sequence and zero
sequence based function. The selection of different operation
modes makes it possible to choose different interaction
possibilities between the negative sequence and zero
sequence based detection.
A criterion based on delta current and delta voltage
measurements can be added to the fuse failure supervision
function in order to detect a three phase fuse failure, which in
practice is more associated with voltage transformer switching
during station operations.
Breaker close/trip circuit monitoring TCSSCBR
The trip circuit supervision function TCSSCBR is designed to
supervise the control circuit of the circuit breaker. The trip
circuit supervision generates a current of approximately 1 mA
through the supervised control circuit. The validity supervision
of a control circuit is provided for power output contacts T1, T2
and T3.
The trip circuit supervision operates after a settable definite
operating time and resets after a settable definite time when the
fault disappears.
10. Control
Synchrocheck, energizing check, and synchronizing SESRSYN
The Synchronizing function allows closing of asynchronous
networks at the correct moment including the breaker closing
time, which improves the network stability.
Synchrocheck, energizing check, and synchronizing SESRSYN
function checks that the voltages on both sides of the circuit
breaker are in synchronism, or with at least one side dead to
ensure that closing can be done safely.
SESRSYN function includes a built-in voltage selection scheme
for double bus and 1½ breaker or ring busbar arrangements.
Manual closing as well as automatic reclosing can be checked
by the function and can have different settings.
For systems, which are running asynchronous, a synchronizing
function is provided. The main purpose of the synchronizing
function is to provide controlled closing of circuit breakers when
two asynchronous systems are going to be connected. The
synchronizing function evaluates voltage difference, phase
angle difference, slip frequency and frequency rate of change
before issuing a controlled closing of the circuit breaker.
Breaker closing time is a parameter setting.
However this function can not be used to automatically
synchronize the generator to the network.
Apparatus control APC
The apparatus control function APC8 for up to 8 apparatuses is
used for control and supervision of circuit breakers,
disconnectors and earthing switches within a bay. Permission
to operate is given after evaluation of conditions from other
functions such as interlocking, synchrocheck, operator place
selection and external or internal blockings.
Apparatus control features:
• Select-Execute principle to give high reliability
• Selection function to prevent simultaneous operation
• Selection and supervision of operator place
• Command supervision
• Block/deblock of operation
• Block/deblock of updating of position indications
• Substitution of position indications
• Overriding of interlocking functions
• Overriding of synchrocheck
• Operation counter
• Suppression of Mid position
Two types of command models can be used:
• Direct with normal security
• SBO (Select-Before-Operate) with enhanced security
Direct commands are received with no prior select command.
SBO commands are received with a select command first and
on successful selection, a proceeding operate command.
In normal security, the command is processed and the resulting
position is not supervised. However with enhanced security, the
command is processed and the resulting position is supervised.
Control operation can be performed from the local HMI under
authority control if so defined.
Generator protection REG650
1MRK 502 050-BEN B
Product version: 1.3
ABB
19