Siemens 7SJ85 - Introduction

Introduction
Capacitors and capacitor banks are used for various applications. Examples are:
•
Reactive-power compensation for voltage stabilization
•
Fast voltage- and reactive-power control
•
Filter circuits for the elimination of certain frequencies
Capacitor banks for transmission systems are complex systems customized for the special application. The
design depends much on the used switching technology (for example, mechanically or via thyristor). In detail
hardly one capacitor bank resembles another. However, a capacitor bank consists always of the same compo-
nents (C, R, L, and switches). A capacitor bank often consists of several subcomponents which are connected
to the capacitor-bank busbar via the circuit breakers.
The modularity of hardware and protection functionality allows to tailor the protection device exactly to the
needs of the capacitor bank or the subcomponent of the capacitor bank and to realize the complete protection
of the whole capacitor bank or the capacitor- bank subcomponent with only one 7SJ8 device.
Capacitor banks require the use of extensive protection functionality. The protection consists of standard
protection functions and specific capacitor protection functions. The following topics are described in the next
chapters:
•
Extensions on standard protection functions for optimal utilization in a capacitor bank
•
Specific capacitor protection functions
•
Application of standard protection functions for specific protection tasks within a capacitor bank
7.1
Capacitor Bank Protection
7.1 Introduction
968 SIPROTEC 5, Overcurrent Protection, Manual
C53000-G5040-C017-8, Edition 07.2017