(1996) Reliability Evaluation of Power Systems一书中介绍的可靠性评估PJM方法有下面几句话: & @. H- l: l# g: }; l+ q A- f5 l3 T" D1) " e6 l |0 E" h- s8 R" bIt is necessary in a practical system to first define an acceptable risk level in order to determine the maximum demand that a particular committed system can meet. : D7 a$ C1 m1 F( z2)Consider, for example, that a risk of 0.001 is acceptable. If additional generation can be made available in System A within 1 hour, the required spinning reserve is only 30 MW and a demand of 170 MW can be supplied.3 v2 t1 h* y9 A* z4 ~
3) In practice an operator would use the PJM risk assessment method by adding, and therefore committing, one unit at a time from a merit order table until the unit commitment risk given by the generation model became equal to or less than the acceptable value for the demand level expected. / g5 x" ^/ ]" P1 x, Y
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原文2句的意思:假设系统允许的风险水平为0.1%。对系统A,若在1h内可以获得额外发电容量的支持,那么,A系统的旋备需求为30MW,可带负荷170MW。, f2 O' _* |) r! Q9 c
1 k2 O4 s8 [) F! ]+ e+ e我的疑问: : {! r- A! _# v* r- w* E从表5.2可见,A系统停运容量大于30的累积概率=运行容量小于170的累积概率=0.0915%,即运行容量大于170概率99.9%,此情形下系统可以带负荷170MW,若还可以获得额外30MW旋备,系统可带负荷就应该是200MW。 . ?% C$ e a* g为何原文讲“170 MW can be supplied”? & L0 R5 `% D8 j$ Z7 b # f; V& J0 {9 ^- I1 K$ f1 @% ? + I( m5 @1 J+ x7 t e& i& \( ^" t