对PJM可靠性方法的疑问

xiaoxue1980

(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：
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It 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.
! G* o5 {, S+ i/ y2）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） 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.
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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。
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我的疑问：
3 `, R) K* ]; w1 ^8 F* J" K; [  M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。
  E+ t' \' F$ U( a为何原文讲“170 MW can be supplied”？

xiaoxue1980

系不系问题太弱，大家不屑一顾嘞？
. K. v) S( Z9 G" T自己顶顶

apsal

旋转备用是系统可以随时顶上来的容量，正常运行时旋转备用并不带负荷，只是在系统发生负荷波动、故障等情况下时才释放旋转备用。
所以200MW的系统供电170MW，旋转备用30MW。
% l$ l# ^0 @/ C8 V/ G5 O% g, @这样可对？

mingyu

PJM电力市场方面的。