ABB Distributed busbar protection REB500

- permissive underreaching transfer tripping

- permissive overreaching transfer tripping

- blocking scheme with echo and transient

blocking functions

• Load-compensated measurement

- fixed reactance slope

- reactance slope dependent on load

value and direction (ZHV<)

• Parallel line compensation

• Phase-selective tripping for single and

three-pole autoreclosure

• Four independent, user-selectable setting

groups.

In the supervision mode the active and reactive

power with the respective energy direction

is displayed by the HMI500.

Autoreclosure

The autoreclosure function permits up to four

three-phase autoreclosure cycles. The first

cycle can be single phase or three-phase.

If the REB500sys autoreclosure function is

employed, it can be used as a back-up for the

autoreclosure realized externally (separate

equipment or in the Main 1 protection).

When the autoreclosure function is realized

outside of REB500sys, all input and output

signals required by the external autoreclosure

equipment are available in order to guarantee

correct functionality.

Synchrocheck

The synchrocheck function determines the difference

between the amplitudes, phase

angles and frequencies of two voltage vectors.

The synchrocheck function also contains

checks for dead line and dead bus.

Transformer differential protection

• For two- and three-winding transformers

• Auto transformers

• Three-phase function

• Current-adaptive characteristic

• High stability for external faults and current

transformer saturation

• No auxiliary transformers necessary

because of vector group and CT ratio compensation

• Inrush restraint using 2nd harmonic

The transformer differential protection function

can also be used as an autonomous T-zone

protection in a 1½ breaker scheme.

Thermal overload

This function protects the insulation against

thermal stress. This protection function is normally

equipped with two independently set

levels and is used when oil overtemperature

detectors are not installed.

Peak value over- and undercurrent protection

These functions are used for current monitoring

with instantaneous response and where

insensitivity to frequency is required.

Peak value over- and undervoltage protection

This function is used for voltage monitoring

with instantaneous response and where insensitivity

to frequency is required.

Frequency function

The function is used either as an over-/ underfrequency

protection, or for load-shedding in

the event of an overload. Several stages of

the frequency protection are often needed.

This can be achieved by configuring the frequency

function several times.

Rate of change frequency protection df/dt

This function is used for the static, dynamic

and adaptive load-shedding in power utilities

and industrial distribution systems. The function

supervises the rate-of-change df/dt of one

voltage input channel. Several stages of the

rate-of-change frequency protection are often

needed. This can be achieved by configuring

the rate-of-change frequency function several

times.

Definite time overfluxing protection

This function is primarily intended to protect

the iron cores of transformers against excessive

flux. The function works with a definite

time delay. The magnetic flux is not measured

directly. Instead the voltage/frequency-ratio,

which is proportional to the flux is monitored.

Inverse time overfluxing protection

This function is primarily intended to protect

the iron cores of transformer against excessive

flux. The function works with an inverse

time delay. The inverse curve ca be set by a

table of 10 values and the times t-min and tmax.

The magnetic flux is not measured directly.

Instead the voltage/frequency-ratio,

which is proportional to the flux is monitored.

Power function

This function provides single, or three phase

measurement of the real or apparent power.

The function can be configured for monitoring

reverse, active or reactive power (power

direction setting). Phase angle errors of the

CT/VT inputs can be compensated by setting.

The operating mode can be configured either

to underpower or to overpower protection.

Logics and delay/integrator

These functions allow the user the engineering

of some easily programmable logical functions