Siemens SIPROTEC 4, User Manual

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Application Scope
The numerical SIPROTEC 4 7SJ62/64 multifunction protection relays are versatile devices designed for protec-
tion, control and monitoring of busbar feeders. The devices can be used for line protection in networks that
are grounded, low-resistance grounded, isolated, or of a compensated neutral point structure. They are suited
for networks that are radial or looped, and for lines with single or multi-terminal feeds. The devices are
equipped with motor protection applicable for asynchronous machines of all sizes.
The devices include the functions that are necessary for protection, monitoring of circuit breaker positions,
and control of the circuit breakers in straight bus applications or breaker-and-a-half configurations; therefore,
the devices can be universally employed. The devices provide excellent backup facilities of differential protec-
tive schemes of lines, transformers, generators, motors, and busbars of all voltage levels.
Protective Functions
Non-directional overcurrent protection (50, 50N, 51, 51N) is the basis of the device. There are three definite
time overcurrent protective elements and one inverse time element for the phase currents and the ground
current. For inverse time overcurrent protective elements, several curves of different standards are provided.
Alternatively, user-defined characteristic can be programmed.
Depending on the version of the device that is ordered, the non-directional overcurrent protection can be
supplemented with directional overcurrent protection (67, 67N), breaker failure protection (50BF), and sensi-
tive ground fault detection for high-resistance ground faults. The highly sensitive ground fault detection can
be directional or non-directional.
In addition to the fault protection functions already mentioned, other protective functions are available. Some
of them depend on the version of the device that is ordered. These additional functions include frequency
protection (81O/U), overvoltage protection (59) and undervoltage protection (27), negative sequence protec-
tion (46) and overload protection (49) with start inhibit for motors (66/68), motor starting protection (48) and
step change protection as well as automatic reclosing (79) which allows different reclosing cycles on overhead
lines. An automatic reclosing system may also be connected externally. To ensure quick detection of the fault,
the device is equipped with a fault locator.
A protection feature can be ordered for the detection of intermittent ground faults which detects and accumu-
lates transient ground faults.
External detectors account for ambient temperatures or coolant temperatures (by means of an external
RTDbox).
Before reclosing after 3-pole tripping the 7SJ623, 7SJ624, 7SJ625, 7SJ626 and 7SJ64 can verify the validity of
the reclosure by means of voltage check and/or synchrocheck. The synchronization function can also be
controlled externally.
Control Functions
The device features a control function for activating and deactivating switchgears via the integrated operator
panel, the system interface, binary inputs, and the serial port using a personal computer with DIGSI.
The status of the primary equipment can be transmitted to the device via auxiliary contacts connected to
binary inputs. The present status (or position) of the primary equipment can be displayed on the device, and
used for interlocking or alarm condition monitoring. The number of operating equipments 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 indications. Depending on the primary equipment being controlled, one binary input
(single point indication) or two binary inputs (double point indication) may be used for this process.
The capability of switching primary equipment can be restricted by a setting associated with switching
authority (Remote or Local), and by the operating mode (interlocked/non-interlocked, with or without pass-
word request).
Processing of interlocking conditions for switching (e.g. switchgear interlocking) can be established with the
aid of integrated, user-configurable logic functions.
Messages and Measured Values; Recording of Event and Fault Data
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.
1.2
Introduction
1.2 Application Scope
SIPROTEC 4, 7SJ62/64, Manual 23
C53000-G1140-C207-8, Edition 08.2016