| The increasing of demand for efficient and clean power supply and the development of information communication technology have accelerated the integration of power system and cyber system,promoting the transformation of tranditional power system into a power cyber physical system(CPS).The addition of cyber system not only facilitates the access of renewable energy and new loads,but also provides the strong support for the safe and economical operation of power system.But the addition of cyber system increases the scale and complexity of power system and brings new risks to power system.If only the failure of physical components is concerned and the impact of cyber system malfunction is ignored in power system reliability evaluation,the result of reliability evaluation will be one-sided.Therefore,it is necessary to evaluate the reliability of power CPS as a whole and incorporate the impact of cyber system malfunctions,so as to obtain more real and comprehensive reliability results,which is of great significance for pratical engineering application.The existing research on the reliability evaluation of power CPS is based on the perspective of equipment,which focuses on the direct or indirect impact of cyber system failures on electrical equipment.But this paper is based on the perspective of power system,exploring the impact of cyber system malfunctions which include bad measurement,lost measurement and remote control malfunction on the state judgement and correction action of power system by dispatchers.The impact is reflected in the modified optimal load shedding model and the power CPS reliability evaluation method is also proposed.The specific research contents of this paper are as follows:(1)Bad measurement is analyzed.Its internal factor is measurement error and external factor is FDIA,which both will lead to state estimation error and mislead the dispatcher’s state judgement of power system.In order to reflect the impact of measurement error and false data on the result of state estimation,the formula of state estimation error considering bad measurement is deducted and the impact mechanism of bad measurement on the judgement and decision of dispatcher and the reliability of power CPS is proposed.RBTS and IEEE-RTS96 are used to perform the simulation to verify the impact of bad measurement on state estimation results.(2)The optimal load shedding model is an effective method to simulate the dispatcher’s correction control action after power system failure.The traditional optimal load shedding model assumes that the system state information is completely accurate and the dispatcher has complete control over the system.In order to reflect the impact of cyber system malfunction in simulation,the traditional optimal load shedding model is modified,incorporating the impact of the state estimation error caused by bad and lost measurement and the uncontrollable correction action caused by remote control outage on the dispatcher’s decision.Based on the modified optimal load shedding model,the power CPS reliability evaluation method using non-sequential Monte Carlo simulation is proposed,which incorporating the cyber system malfunctions into reliability evaluation.Because of the lack of cyber system struction of test systems,the cyber system structures of RBTS and IEEE-RTS96 are constructed,respectively.The reliability evaluation of test systems verifies the effectiveness of the proposed power CPS reliability evaluation method and reflects the impact of cyber system malfunction on power CPS reliability. |
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