A cost effective security dispatch methodology

Abstract

This paper deals with the problem of formulating dispatching algorithns which must trade off power system o p e r a t i n g c o s t w i t h system s e c u r i t y e f f e c t s . D e c ision theory was used t o s t r u c t u r e o p t i m i z a t i o n a l g orithms which dispatch a power systeminaccordance with d i f f e r e n t s e c u r i t y s t r a t e g i e s . The s t r a t e g i e s thems e l v e s a r e d i c t a t e d by how one w i s h e s t o t r e a t p r o b a b il i s t i c l o a d v a r i a t i o n s and contingency events. The c h i e f v a l u e o f t h i s r e s e a r c h l i e s i n p r o v i d i n g an approach t o u n i f y i n g t h e t e c h n i q u e s o f s t o c h a s t i c power flows, contingency analysis and constrained optimizat i o n . A. INTRODUCTION The b a s i c p r o b l e m d e a l t w i t h i n t h i s p a p e r can be sumnarized as: "What i s t h e b e s t way t o s t r u c t u r e and implementa power dispatching system which meets severe system security requirements?" Contingency analysis, p r o b a b i l i t y , c o n s t r a i n e d o p t i m i z a t i o n and decision theory are applied in answering this question. Contingency analysis a1 lows a dispatch operator to repeatedly pose various hypothetical "what if" events which could occur i n t h e power system, and to analyze t h e i r e f f e c t s . U s u a l l y some s o r t o f s t e a d y s t a t e model o f t h e power system, i n i t i a l i z e d t o p r e s e n t c o n d i t i o n s , i s used to provide the answers t o t h e h y p o t h e t i c a l questions. O f major importance are the questions "What i s the relative importance o f one hypothetical contingency event versus another?" and "Given that one o r more of the events occur, what canbedone about i t and what cost penalty should be applied?" The " r e l a t i v e importance" of one contingency event versus another depends upon t h e p r o b a b i l i t y t h a t t h e e v e n t w i l l occur and upon the probable effects of the event given that i t has occurred. Thus, contingency analysis and probab i l i t y t h e o r y must be combined. P r o b a b i l i t y t h e o r y i s used t o d e t e r m i n e t h e p r o b a b i l i t y o f f a i l u r e o f system components (e.g., line or generator outages) and t o det e r m i n e t h e p r o b a b i l i t y o f d i f f e r e n t l o a d d i s t r i b u t i o n s . C a l c u l a t i n g t h e p r o b a b i l i t y of various contingency events and t h e e n s u e i n g p r o b a b i l i t i e s o f t h e e f f e c t s o f t h o s e events provide a method o f comparing one event and i t s effects to another event and i t s e f f e c t s . S t i l l needed, however, i s an answer to the question "How r e l i a b l e should the system be and what i s the cost associated w i t h t h a t r e l i a b i l i t y ? " I t may be assumed t h a t : 1. a f i x e d r e l i a b i l i t y i s t o be maintained, or Engineering Committee of the IEEE Power Engineering Society for presentation at Paper F 75 427-5, recommended ...

Probabilistic security analysis of shipboard DC zonal electrical distribution systems

“…The mathematical models of the power converter equivalent circuit in Fig. 2 are shown in (1) to (5). Since the modeling of the power inverters is similar to that of controlled rectification, this model can be also applied for the power inverters except that the values of the dc equivalent communication resistance and dc current shown in (1) to (5) are changed to be negative [7].…”

“…Literatures relevant to the power system probabilistic security analysis are focused on utility transmission systems [5,6]. Works on industrial power systems, such as shipboard power systems, are still limited.…”