Introduction
1.2 Application Scope
SIPROTEC, 7SJ62/64, Manual
C53000-G1140-C207-2, Release date 01.2008
24
1.2
Application Scope
The digital SIPROTEC 4 7SJ62/64 multifunction protection relays are versatile devices designed for protection,
control and monitoring of busbar feeders. The devices can be used for line protection in networks that are
grounded, low-resistance grounded, ungrounded, 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 protective
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 cur-
rent. For inverse time overcurrent protective elements, several curves of different standards are provided. Al-
ternatively, user-defined characteristic can be programmed.
Depending on the version of the device that is ordered, the non-directional overcurrent protection can be sup-
plemented with directional overcurrent protection (67, 67N), breaker failure protection (50BF), and sensitive
ground fault detection for high-resistance ground faults. The highly sensitive ground fault detection can be di-
rectional 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 pro-
tection (81O/U), overvoltage protection (59) and undervoltage protection (27), negative sequence protection
(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 RTD-
box).
Before reclosing after three-pole tripping the 7SJ623, 7SJ624 and 7SJ64 can verify the validity of the reclosure
by means of voltage check and/or synchrocheck. The synchronization function can also be controlled external-
ly.
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 plausibility monitoring. The number of the operating equipment 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 posi-
tion 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.
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