Shunt Capacitor Bank Fundamentals and Protection

2003 Conference for Protective Relay Engineers - Texas A&M University April 8-10, 2003, College Station (TX)

Shunt Capacitor Bank Fundamentals and Protection

Gustavo Brunello, M.Eng, P.Eng Dr. Bogdan Kasztenny Craig Wester

GE Multilin, Canada [e-mail]

GE Multilin, Canada [e-mail]

GE Multilin, USA [e-mail]

ABSTRACT

Shunt capacitor banks are used to improve the quality of the electrical supply and the efficient operation of the power system. Studies show that a flat voltage profile on the system can significantly reduce line losses. Shunt capacitor banks are relatively inexpensive and can be easily installed anywhere on the network.

This paper reviews principles of shunt capacitor bank design for substation installation and basic protection techniques. The protection of shunt capacitor bank includes: a) protection against internal bank faults and faults that occur inside the capacitor unit; and, b) protection of the bank against system disturbances.

Section 2 of the paper describes the capacitor unit and how they are connected for different bank configurations. Section 3 discusses bank designs and grounding connections. Bank protection schemes that initiate a shutdown of the bank in case of faults within the bank that may lead to catastrophic failures are presented in Section 4. The paper does not address the means (fuses) and strategies to protect individual elements or capacitor units, nor the protection of capacitor filter banks. System disturbances and basic capacitor bank control strategies are also discussed.

1. INTRODUCTION

Shunt capacitor banks (SCB) are mainly installed to provide capacitive reactive compensation/ power factor correction. The use of SCBs has increased because they are relatively inexpensive, easy and quick to install and can be deployed virtually anywhere in the network. Its installation has other beneficial effects on the system such as:

References: (1) IEEE Std C37.99-2000, IEEE Guide for the Protection of Shunt Capacitors Banks Biographies: Gustavo Brunello received his Engineering Degree from National University in Argentina and a Master in Engineering from University of Toronto. For several years he worked with ABB Relays and Network Control both in Canada and Italy. In 1999, he joined GE Power Management as an application engineer where he is responsible for the application and design of protective relays and control systems. Gustavo is a Professional Engineer of the Province of Ontario and a member of the IEEE. Bogdan Kasztenny received his M.Sc. and Ph.D. degrees from the Wroclaw University of Technology (WUT), Poland. He joined the Department of Electrical Engineering of WUT after his graduation. Later he was with the Southern Illinois University in Carbondale and Texas A&M University in College Station. From 1989 till 1999, Dr. Kasztenny was involved in a number of research projects for utilities, relay vendors and science foundations. Since 1999 Bogdan works for GE Power Management as a Chief Application Engineer. Bogdan is a Senior Member of IEEE, has published more than 100 technical papers, and is an inventor of 5 patents. His interests focus on advanced protection and control algorithms for microprocessor-based relays, power system modeling and analysis, and digital signal processing. Craig Wester received his B.S. in Electrical Engineering with a strong emphasis on power systems from the University of Wisconsin-Madison in 1989. Craig joined General Electric in 1989 as a utility transmission & distribution application engineer. Currently, he is the Regional Sales Manager (Southern US) for GE Multilin. His role consists of providing sales management, power system protection application and support to the investor-owned utilities, rural electric cooperatives, electric municipals, consultants, and OEMs throughout the southern US for GE relaying equipment. Craig is a member of the IEEE.