The frequency characteristics of islanding operation are introduced firstly. The magnitude of balance between electromagnetic power and the original motive power and the inertia of the system are the critical factors that affect the frequency. Based on the possible over-frequency problems during the isolated operation of the regional network, the configuration principles of over frequency generator tripping are proposed. Taking an actual grid as an example, an adaptable and efficient configuration solution of over frequency generator tripping is made according to the principles. In addition, the coordination between over frequency generator tripping and over-speed protection controller is studied. This paper brings forward meaningful reference configuration principles for over frequency generator tripping that is suitable to small-capacity regional power grid which is in infirm interconnections.

In order to maximize the match between the output of the Hybrid Wind/Photovoltaic/ Energy storage System and the scheduling curve,the article takes the measure that optimizes and controls the energy storage device one day ahead.Due to the fuzziness of the wind and photovoltaic output, the optimal control method of energy storage is proposed based on a fuzzy dependent-chance programming theory. This method considers the constraints of the energy storage device including the power output and energy constrain, and the matching degree of each time is represented by credibility value.So the final goal is maximizing the mean value of the total credibility within a day of 96 periods.The genetic algorithm based fuzzy simulation is used to solve the model,then we can get the different periods of energy storage charge and discharge power corresponding to the credibility of maximum mean value.

Aiming at the problem of electric vehicle charging station planning, the clients of fast charging stations is analyzed. The optimal mathematical model about siting of electric vehicle charging stations is proposed based on the city's geographic information. We obtain the optimal location of charging stations by charging convenient factor as a constraint. And divide the load area which is served by each charging station by the Voronoi. According to the load which is served by each charging station, this paper designs the optimal battery charger number of each charging station with the Queuing Theory. Finally, optimize the charging convenient factor using the total cost as objective function. The analysis of examples verifies the effectiveness and the practicability of the proposed planning approach.

The study on the HVDC based on voltage-source converter focuses mainly on the control strategy while less on the impact of electrical damping on the adjacent units by VSC-HVDC. The mechanism of VSC-HVDC on inhibiting sub-synchronous oscillation is analyzed theoretically in the respect of its operation principle. Then the complex torque coefficient method realized by time domain simulation-the test signal method, is adopted to investigate the impact of the unit interaction factor, control mode, active power level and reactive power level on the electrical damping on the adjacent units.

Large-scale wind turbine generators with power electronic converters that operate near series compensated transmission lines are susceptible to un-damped sub-synchronous oscillations. This sub-synchronous oscillation is called Sub-synchronous Control Interaction (SSCI). With the rapid development of wind power technology, SSCI emerges as a new sub-synchronous oscillation phenomenon. The first SSCI event occurred for a wind farm in America in2009, which resulted in damage to the wind turbines. The origin of SSCI is presented and its characteristics of different types of wind turbines are summarized. Then the research prospect on this field is explored.