Identification; Application - ABB Relion REC670 Applications Manual

Section 7
Current protection
7.15.1

Identification

Capacitor bank protection
7.15.2

Application

Shunt capacitor banks (SCBs) are somewhat specific and different from other power system
elements. These specific features of SCB are briefly summarized in this section.
A capacitor unit is the building block used for SCB construction. The capacitor unit is made up
of individual capacitor elements, arranged in parallel or series connections. Capacitor
elements normally consist of aluminum foil, paper, or film-insulated cells immersed in a
biodegradable insulating fluid and are sealed in a metallic container. The internal discharge
resistor is also integrated within the capacitor unit in order to reduce trapped residual voltage
after disconnection of the SCB from the power system. Units are available in a variety of
voltage ratings (240V to 25kV) and sizes (2.5kVAr to about 1000kVAr). Capacitor unit can be
designed with one or two bushings.
The high-voltage SCB is normally constructed using individual capacitor units connected in
series and/or parallel to obtain the required voltage and MVAr rating. Typically the neighboring
capacitor units are mounted in racks. Each rack must be insulated from the other by insulators
because the can casing within each rack are at a certain potential. Refer figure
example:
164
Function description IEC 61850 IEC 60617
identification identification
CBPGAPC -
1MRK 511 358-UEN A
GUID-67FC8DBF-4391-4562-A630-3F244CBB4A33 v2
ANSI/IEEE C37.2
device number
-
GUID-5EC8BAEC-9118-49EC-970C-43D6C416640A v1
GUID-BACAE67B-E64B-4963-B323-ECB0B69031B9 v2
76 for an
Application manual