Application Scope - Siemens SIPROTEC 4 7VK61 Manual

Introduction

1.2 Application Scope

1.2 Application Scope
The 7VK61 breaker management relay is a multi-purpose starting and control device for automatic and
manual closing of circuit breakers in electrical networks of all voltage levels.
The automatic reclose function may be used on overhead lines for single-pole, three-pole or single- and three-
pole automatic reclosure as well as multi-shot automatic reclosure. The adaptive dead times can be set individ-
ually for single-pole, three-pole auto-reclosure and for additional (up to 8) reclose cycles.
Before reclosure after three-pole tripping, the validity of the reclosure can be checked by synchronism check
by the device (can be ordered optionally). Alternatively, the de-energization of the line or of the busbar can be
checked. If desired, asynchronous energization is also possible. In this case, the device calculates the moment
of the energization command so that the two voltages at busbar and feeder are in phase the instant the
circuit-breaker poles make contact.
The circuit breaker must be suitable for auto-reclosing. For single-pole auto-reclosure the poles must be indi-
vidually controllable. The device considers whether the circuit breaker is ready for a trip and close cycle and its
position - provided this information is supplied by the circuit breaker. The breaker recovery time can be moni-
tored. During single-pole auto-reclosure the relay can either process the parallel connection or the series
connection or both connections of the auxiliary contacts at the circuit breaker poles. The relay is furthermore
capable of processing the auxiliary contact of each pole. But generally the relay can operate without such
information from the circuit breaker.
7VK61 can work together with static and digital protection equipment requiring only pickup and trip opera-
tions from them. For single-pole auto-reclosure the trip signals must either be distinguished as to whether
they are single-pole or three pole or they must be transmitted to the relay for each pole separately. In the
event of three-pole auto-reclosure alone a general trip signal is sufficient.
Protective Functions
The 7VK61 features the following basic functions:
•
Auto-Reclose function
•
Synchronism and Voltage Check
•
Circuit Breaker Failure Protection
•
Under/Overvoltage Protection
•
Backup overcurrent
Control Functions
The device is equipped with control functions which operate, close and open, switchgear devices via control
keys, the system interface, binary inputs and a PC with DIGSI software. The status of the primary equipment
can be transmitted to the device via auxiliary contacts connected to binary inputs. The present status (or posi-
tion) of the primary equipment can be displayed on the device, and used for interlocking or plausibility moni-
toring. The number of the devices to be switched is limited by the binary inputs and outputs available in the
device or the binary inputs and outputs allocated for the switch position feedbacks. Depending on the mode
of operation, one binary input (single point indication) or two binary inputs (double point indication) can be
used. The capability of switching primary equipment can be restricted by appropriate settings for the
switching authority (remote or local), and by the operating mode (interlocked/non-interlocked, with or
without password validation). Interlocking conditions for switching (e.g. switchgear interlocking) can be
established using the integrated userdefined logic.
Indications and Measured Values; Fault Recording
The operational indications provide information about conditions in the power system and the device. Meas-
urement quantities and values that are calculated can be displayed locally and communicated via the serial
interfaces.
Device messages can be assigned to a number of LEDs on the front panel (programmable), can be externally
processed via output contacts (programmable), linked with user-definable logic functions and/or issued via
serial interfaces (see Communication below).
20 SIPROTEC 4, 7VK61, Manual
C53000-G1176-C159-5, Edition 05.2018