Dynamic Security Assessment
Leonard L. Grigsby · 2007
Power system security in the context of this chapter is concerned with the technical performance and quality of service when a disturbance causes a change in system conditions. Strictly speaking, every small change in load is a disturbance that causes a change in system conditions; however, this topic focuses on what could be called ‘‘large changes’’ in system conditions. These changes are referred to as ‘‘contin- gencies.’’ Most commonly, contingencies result in relay operations that are designed to protect the system from faults or abnormal conditions. Typical relay operations result in the loss of a line, transformer, generator, or major load.