Research And Exploitation On Verification System For Power Setting Of Relay Protection

Based on the traditional value simulation verification system，this system isadded protection device operating characteristics to realize device level valuesimulation. In other words, the simulation verification system can simulate the actionlogic of various protection devices, so the value of protection devices can be judgedwhether meet the operating conditions of current system or not. At the same time, theanalysis of verification results based on the importance of protection is proposed toserialize the protection value that does not meet the requirements of verification,which helps value maintenance staff develop a reasonable way of value maintenanceprograms and arrangements.Firstly, logic judgment method and value judgment method are analyzed in thispaper. Value judgment method has more advantages in authenticity than logicjudgment method, while logic judgment method has more advantages in coordinationof protection than value judgment method. Thus, both advantages above are used insimulation verification software. At the same time, the operation models andcharacteristics of protection are introduced to improve the authenticity and reliabilityof simulation.Secondly, the establishment method of protection models based on theknowledge base of expert system and the design of inference engine are introduced.Knowledge base of expert system is established with knowledge element which isknowledge framework theory after abstraction and modularity of object structure. Thecharacteristics of expert system inference engine are analyzed. Positive reasoning isused in the simulation method of protection operation combined with thecharacteristics of protection operation. At the same time, the simulation operation ofrelay protection includes single type of protection operation simulation and varioustypes of protection operation simulation, which can reflect the coordination of relaysand make simulation verification more realistic and reliable.Thirdly, the necessity of protection importance is analyzed and the protectionvalue that needs correction and improvement is serialized, which helps protection anddispatching staff develop a reasonable way of value maintenance programs andarrangements. Then, set distance protection as an example, risk theory is used tocalculate the probability of protection that refuse to operate and operate incorrectly.The protection importance of protection device is calculated in three aspects thatcontain load isolation, generator isolation and overload of transmission line. Thelarger the protection importance of protection device is, the more important theprotection device is. So this device is handled preferentially to avoid large-scaleblackouts.Finally, all functions of verification system which are based on the input ofactual grid information, the simulation verification process of protection value and thesimulation verification reports of protection value. Moreover, the simulationverification is applied in actual grid to verify the effectiveness of verification system.