Regulus uREG, User Manual

Page: 10 / 107

uREG User Manual
10
3. FUNCTIONS AND FEATURES
(depending on the developed APPLICATION)
The most important features:

Short-circuit overcurrent fault protection (ANSI 50/51) from effects of line-to-line short-circuit
fault with an independent single-stage characteristic curve. For the short time after operational
power-up of a bay, current and time settings can be dynamically modified by adjustable
increments to shift the tripping shutdown point. Increments become inactive after successful
closing. The protection function can be deactivated. Activation is possible.

Time-dependent overcurrent protection (51) provides three dependent time-current
characteristic curves with a different slope: moderate, standard and rapid. Tripped protection
results in shutdown. The protection function can be shut down.

Overcurrent protection against overloading (51) with one-stage feature. The protection can be
shut down, set to respond to a signal or trip-out.

Negative sequence overcurrent fault protection (51_2).

Directional power interlock (32) for any protective function (67).

Voltage (59) protective functions including the overvoltage (59P) fault protection and the
undervoltage (59U) fault protection , both of which have independent characteristic curves;
they are of single-stage type; optionally to be shut down; they can cause local and general-
substation (UP) alarms or tripping; for both cases, it is possible to select the increase (decrease)
mode for one voltage or all voltages simultaneously.

Line-to-earth short-circuit fault protections group according to selectable criteria relating to:
overcurrent (directional or nondirectional)with an independent characteristic curve, admittance
and susceptance. The unit is equipped with a common input for Ferranti-Holmgreen filters.
Protective functions can be shut down, and used to activate local or substation (UP) alarms or
cause trip-out. Admittance criteria are activated once threshold U0> (predefined by setting) is
exceeded.

Under (81L) and overfrequency (81O) fault protection.

Derived frequency criterion (df/dt) (81R – Rate-Of-Change Of Frequency).

‘Vector shift’ criterion (three-phase type), adjustable within the range of 1 to 25 angle degrees
(measuring accuracy 0.5 deg), instantaneous (internal time approx. 30 ms).

Current asymmetry criterion (60P).

Differential fault protection (87, 87T, 87G) for each phase with multi-slope bias characteristics
and selectable slope knee point. Ideally suited for the protection of transformers with two or
three windings configured in one of the most popular vector group (Yy0,Yy6,Yd1,Yd5,Yd7,Yd11).
In this case 2
nd
and 5
th
harmonic restraint functions can be applied. The differential protection
function is also suitable for generators and large motors against two or three phase internal
faults and inter-turn faults.

Three-phase overpower (P3f>) and underpower (P3f<) protection for active power with an 1-
second average, adjustable for the active power value across device terminals within the range
of 10 to 1000 W (easily converted into primary power by multiplying the setting by the thetaIf
current transformation ratio and voltage transformation ration – i.e. 150 for the 15 kV grid),
with directional setting in three modes: non-directional, positive power direction, negative
power direction.

Three-phase overpower (Q3f>) and underpower (Q3f<) protection for reactive power with an
1-minute average, adjustable for the reactive power value across device terminals within the
range of 10 to -1000 var (easily converted into primary power by multiplying the setting by the
thetaIf current transformation ratio and voltage transformation ration – i.e. 150 for the 15 kV
grid), with directional setting in three modes: non-directional, positive power direction, negative
power direction.

Cooperation with external protective devices via terminals of input signals.