Frequency Overrun Standard And New Control Strategy

Power system frequency is an important indicator of power quality, and the most important parameters in power system operation. If the power supply and demand balance in the power system, the frequency of the system will maintain the rating,otherwise, the frequency will change, system will be followed by a means of regulation and secondary regulation, make a series of automatic or manual power adjustment to meet the frequency requirements.In order to ensure the system power supply and demand balance, each control area uses automatic generation control system to ensure control area power generation, power load and tie-line trade balance. In order to regulate and guide control behavior of the various automatic generation control system, need to study the corresponding control performance evaluation criteria to evaluate the behavior of their control.At present, China power grid using in the performance evaluation criteria is the North American standard CPS directly or simply applied,which is called class CPS, in CPS, the frequency indicators are long-term statistical indicators. Studying and evaluating long-term performance of the control area with statistical indicators, will help the control area "to atone", you can save a lot of energy consumption, but also effectively avoid the phenomenon of anti-tune the production. But it will also flood the instantaneous frequency influence to the system, because if a (some) control area due to some reasons (such as:lack of regulation, speculation, etc.) failed to meet the regulation requirements, the frequency will affect the quality of the whole system, resulting in a large instantaneous frequency difference which can cause a large security risk in the system (because the frequency difference in the frequency of qualified outer limit of the instantaneous value, if the frequency the greater the amount of overrun, it means that the power imbalance in the system more large, the smaller the margin of safety systems). Thus, in the CPS by the class of indicators to ensure the statistical properties of the system frequency, the frequency difference in the need for qualified outside limit of the instantaneous frequency values of the behavior of each control area to evaluate.At first the paper describes the basic principles of power system load frequency control and general process of automatic generation control, analysis the effect of controlled areas of the interconnected power system AGC control mode detailed, analysis the CPS standard comprehensively, and after analyzing the application of CPS standard by simple changing, CPS standard is not suitable for the actual situation of China's interconnected power system, Also, according to corporate standards of our serious consideration, found there is a certain one-sidedness in CPS standards, it is that it only consider the frequency of statistical indicators, but indicator of the instantaneous frequency is studied. To solve the above problem, I designed a kind of standard which is to evaluate the ability of frequency control when iinstantaneous frequency beyond the limit, called the CPS3. According to its characteristics, I designed the AGC control strategy based on moving average theory, and with the former CPS1 and CPS2 control strategy coordinated output, to ensure system security and reliable operation. The results indicate that the target for reducing the times of the frequency beyond the limit can give great help on ensuring the security and reliability of grid operation.