In order to effectively adjust and control the motion amplitude of the flexible manipulator and avoid large deviation between the actual motion track of the flexible manipulator and the target track，a flexible manipulator motion track control system based on the combination of distributed control system （DCS） and inertial weight was designed. It is a computer system that integrates computer，communication，display and control and is controlled by process control and process monitoring. The DCS algorithm was used to control the behavior amplitude of the monitored object and calculate the inertia weight of the flexible manipulator. The DCS-inertia weight combination was used to solve the specific value of the prime control index. The software design of the flexible manipulator motion trajectory control system was realized. The experimental results show that the motion amplitude of the end coordinates of the manipulator in the horizontal，vertical and spatial axes under the action of the DCS-inertia weight combination algorithm can be controlled within 10 units of length，and the optimal control state of the manipulator's motion trajectory can be entered within 0.52 s，with the maximum difference of the motion trajectory being only 0.01 rad，which verifies the feasibility and effectiveness of the system.

In order to solve the problem of low accuracy of small substation fault diagnosis，a small substation fault diagnosis model based on cooperative game and cloud model was proposed. By analyzing the characteristics and causes of faults，the diagnosis index system was established. Entropy method and expert weighting method were used to obtain index weight，cooperative game method was used to calculate consistency coefficient and combination weight，and the final fitting weight was obtained through normalization. Through the cloud model，the quantitative expression of each index was realized，and the weighted deviation degree was obtained. According to the weighted deviation degree，the final diagnosis result was determined. The experimental results show that the index weight distribution of the established model meets the consistency requirements，and the diagnostic accuracy of fault location and degree is high，which can provide more guarantee for the safe operation of substation.

In view of the frequent occurrence of omissions and false alarms of partial discharge insulation defects in on-site gas insulated switchgear（GIS），the partial discharge multi-source detection test platform was built by using true GIS to carry out the intermittent discharge test of metal contamination defect on the surface of insulator. Different partial discharge detection methods were used to study the variation of intermittent discharge characteristics of different discharge degrees. The research results show that the discharge amount of metal contamination defect shows a trend of first increasing and then decreases with the prolongation of discharge time；the overall discharge time interval shows an increasing trend；ultrasonic detection method and chemical detection method cannot realize the effective perception of intermittent discharge of metal contamination defect；the distribution law of intermittent discharge can be preliminarily obtained from the 200 frequency period ultra high frequency（UHF）phase-resolved partial discharge（PRPD）spectrum composed of 4 groups of 50 frequency period UHF PRPD spectrum data；metal contamination defect in intermittent discharge state will not gradually evolve into breakdown discharge failures. The research results are of great significance for expanding the cognition of intermittent discharge characteristics and the field detection of GIS discharge defects.

The motor actuator used in circuit breaker has the advantages of simple structure，small dispersal of action and strong controllability，which provides the possibility for the switch contact of circuit breaker to follow the preset reference curve. The traditional control method can not adjust the parameters according to the movement process of circuit breaker switch contact，and the following is poor，and the intelligent control algorithm is complicated in calculation，affects the rapidity of control system，and is extremely difficult to implement in engineering. A piecewise pseudo-differential control strategy was presented，which avoids direct differentiation of the controlled variables and has the ability of fast dynamic response and anti-interference. Meanwhile，the control system parameters were given according to the segmented environment to ensure the following accuracy. The control strategy model was established for simulation analysis，and the 126 kV circuit breaker motor actuator control system was developed for experimental verification. The simulation and experimental results show the effectiveness of the control strategy.

As a new type of compressor，linear compressor has the advantages of high efficiency，small volume，low noise and little vibration. However，in order to give full play to its advantages of high efficiency，it is necessary to control the driving frequency to track its mechanical resonance frequency. According to this characteristic，a frequency tracking control algorithm of linear oscillation motor based on second-order generalized integrator （SOGI） and double correlation phase detection algorithm was proposed. Compared with the frequency tracking control algorithm based on the average value of stroke-current product （ASCP），the control algorithm has the advantages of fast dynamic response and stable operation under variable working conditions，enhances the suppression effect of external interference and improves the stability of the control system. Simulation and experiments show that the proposed control algorithm can quickly track the natural frequency of the motor，which verifies the rationality and effectiveness of the theory.

In high-precision applications，the control accuracy of the servo system is extremely high required. The control precision of the servo system depends largely on the precision of the feedback measurement. Position and speed feedback accuracy can be improved by increasing the absolute accuracy of the encoder，and it is not sensitive to external interference，while the current sampling link is more sensitive to switching noise，which will cause torque fluctuation and reduce the control precision of the servo system. Based on the principle of high-precision current sampling in servo system，the influence of switching noise on current control accuracy was studied. An SINC3 filter structure with continuous output and a method to improve the steady-state current control accuracy were proposed. The experimental results show that the method has obvious effect on restraining the current fluctuation caused by switching noise，and has strong engineering guiding significance.

A quasi-resonant Flyback（QR-Flyback） converter with 65 W output was designed. The valley switching principle and the switching loss reduction mechanism of QR-Flyback were analyzed，the frequency and loss characteristics of the system under different working conditions were compared，and the advantages and disadvantages of frequency conversion control were summarized. Combined with the frequency hopping control function of the NCP1380 controller，the hardware circuit parameters of each part of the system were designed and the efficiency of the system was effectively improved. Finally，the feasibility of theoretical analysis and parameter design were verified by simulation and experiment.

The secondary voltage signal output by electronic capacitive voltage transformer in the primary and secondary fusion equipment is very weak，which is easy to be interfered by high-order harmonics，resulting in unstable signal transmission. In order to solve these problems，a high-order and high-precision filter based on Sallen-Key was proposed to suppress harmonics and reduce the interference to the working signals. Firstly，the working principle of the transformer was analyzed. Then，based on the principle and the working frequency band of the primary and secondary fusion equipment，the integration circuit and filter circuit were studied and designed with Matlab/Simulink simulation software. Finally，the filtering circuit was optimized and the whole circuit was simulated. The results show that the optimized circuit can suppress the interference of high-order harmonics more effectively and ensure the stable output of fundamental wave.

Aiming at the problems of three-phase load imbalance，power quality degradation and harmonic dispersion in current electronic power distribution system，a comprehensive power quality control scheme with fast dynamic response and small output harmonic was proposed，which includes comprehensive control mode and compound repeat control strategy. By example analysis，it is found that harmonic content decreases before and after compensation in a specific subharmonic compensation mode. After the unbalanced grid compensation，the current distortion was eliminated and the voltage and current were in the same phase，which indicates the effectiveness of the comprehensive management. In the experimental verification，the continuous output of 25 kW inductive reactive power to 25 kW capacitive reactive power was realized，the requirements of reactive power regulation -100%~100% in the technical index was met，and the deviation between the output power and the command value was only 0.49%，the requirements of less than 3% in the technical index were met. In addition，the compensated three-phase grid current THD was reduced to 4.7%，after unbalance compensation treatment，the unbalance degree was reduced to 1.4%，which shows the effectiveness of the device in the treatment of three-phase load unbalance，power quality degradation and harmonic dispersion.

In order to improve the short-circuit breaking capacity of solid-state circuit breaker （SSCB） in DC system，a multi-objective optimization method that explores component parameters to achieve optimal breaking characteristics was proposed. A detailed analysis of the breaking process of the SSCB during a short-circuit fault was performed，and the influence of the current limiting inductor LB and the voltage limiting capacity factor γ of the metal oxide varistor （MOV） on the breaking characteristics was investigated by theoretical analysis and simulation. Based on the breaking characteristics，three optimization objective functions of breaking impact performance，breaking time and energy absorption were established. The objective functions were optimized by the multi-objective particle swarm algorithm，and a method which combines technique for order preference by similarity to ideal solution and decision maker preferences，was used to make decisions. The results show that under different decision maker preferences，the component parameters L_B and γ after the optimization can significantly improve the breaking performance of the SSCB.