Two-area analysis of system time deviation and inadvertent interchange energy accumulation in interconnected power systems

摘要

System time deviation and inadvertent interchange energy of an area are considered as a vector with two coordinates. For any one control area, the rest of the interconnection is considered as one equivalent area. The two-dimensional vector which represents system time deviation (epsilon) and inadvertent interchange energy I can be decomposed into two vector components: a component caused by the area itself, and a component caused by the rest of the interconnection. The former vector component represents the area component of the system time deviation and the primary component of inadvertent interchange energy as defined by Nathan Cohn. The latter vector component represents the area component of system time deviation and the secondary component of inadvertent interchange energy caused by the rest of the interconnection as defined by Cohn;The concept of vector decomposition can be illustrated on the two-dimensional Cartesian plane. This plane is called the ((epsilon),I) plane. Some properties of the effect of the control actions on system time deviation and inadvertent interchange energy are discussed. Control actions investigated are the automatic generation control actions and/or corrective control actions in and/or outside an area. Various corrective control schemes are investigated and illustrated. These corrective control schemes are compared in terms of energy (MWH) required for the control action;The causes of excessive accumulation of inadvertent interchanges encountered in the Western System Coordinating Council are investigated. The possible situations that can lead to excessive accumulation of inadvertent interchanges in the area of interest are investigated using an Automatic Generation Control (AGC) simulation program. Selective participation in the continuous, automatic time error correction scheme is also investigated;The validity of the decomposed vector components of an area itself and of the rest of the interconnection is checked using the AGC computer program. These results confirm the validity of the concept of vector decomposition;Finally, three examples of debit/credit computation, based on area components of system time deviation, are presented. With the help of the debit/credit system, the inadvertent interchange energy accounts of control areas can be adjusted properly in order to correct the system time deviation to zero with a minimum amount of regulation (MWH) in the whole interconnected power systems.