Applications - Siemens SIPROTEC 7SJ62 Instruction Manual

1.2

Applications

Protective
Functions
Control Functions
7SJ62 Manual
C53000-G1140-C121-1
The numerical, multi-functional SIPROTEC
for many applications. The 7SJ62 can be used as a protective, control, and monitoring
device for distribution feeders and transmission lines of any voltage in networks that
are grounded, low-resistance grounded, ungrounded, or of a compensated neutral
point structure. The device is suited for networks that are radial or looped, and for lines
with single or multi-terminal feeds. The 7SJ62 is equipped with motor protection appli-
cable for asynchronous machines of all sizes.
The 7SJ62 includes the functions that are necessary for protection, monitoring of cir-
cuit breaker positions, and control of the circuit breakers in straight bus applications or
breaker-and-a-half configurations; therefore, the device can be universally employed.
The 7SJ62 provides excellent backup facilities of differential protective schemes of
lines, transformers, generators, motors, and busbars of all voltage levels.
Non-directional overcurrent protection (50, 50N, 51, 51N) is the basis of the 7SJ62.
Four definite-time overcurrent protective elements exist, two for the phase and two for
the ground (50 and 50N) currents. The elements can be set with no time delay, where
instantaneous tripping is desired. Inverse-time overcurrent protective elements are
also available for both the phase and the ground (51 and 51N) currents. The common
U.S. ANSI time-characteristics are also available. Alternatively, user-defined charac-
teristics can be programmed or IEC characteristics can be selected.
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 sensitive ground fault detection for high-resis-
tance ground faults or systems that are resistively grounded (50 Ns, 67Ns). The highly
sensitive ground fault detection can be directional or non-directional.
Other protective functions are available, some of which depend on the version of the
device that is ordered. These additional functions include negative sequence (phase
balance) current protection (46), automatic reclosing (79), thermal overload protection
(49), overvoltage protection (59), undervoltage protection (27), and over/under fre-
quency protection (81O/U). For motor protection, starting time supervision (48), start
inhibit (66/68), and undercurrent monitoring (37) are optionally available. Finally, the
7SJ62 is equipped with a fault locator.
The 7SJ62 supports all control and monitoring functions that are required for operating
medium to high-voltage substations. A major application is the reliable control of
switchgear or circuit breakers. Such control can be accomplished via the integrated
operator panel, the system interface, the binary inputs, and the serial port using a per-
sonal computer with DIGSI
The status of the primary equipment or auxiliary devices can be transmitted to the
7SJ62 via auxiliary contacts connected to binary inputs. The present status (or posi-
tion) of the primary equipment can be displayed on the 7SJ62, and used for interlock-
ing or, if applicable, plausibility monitoring. Only the quantity of binary inputs and out-
puts available in the 7SJ62 limits the number of primary devices that can be operated.
Depending on the primary equipment being controlled, one binary input (single indica-
tion) or two binary inputs (double indication) can be used in the position monitoring
process.
The capability of switching primary equipment can be restricted by a setting associat-
ed with switching authority – Local, DIGSI
mode – Interlocked or Non-Interlocked, with password request. Processing of inter-
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4 7SJ62 is a versatile device designed
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4 PC, or Remote, and by the operating
Introduction
1-5