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The invention belongs to the field of large power grid transient frequency control strategies, and particularly relates to a wind/thermal power combined frequency control method based on a virtual weight coefficient. The method comprises the following steps: establishing a comprehensive frequency response model; constructing a robust comprehensive frequency response model containing RES; performing inertia control analysis; and performing frequency secondary response analysis. According to the invention, a robust comprehensive frequency response model containing virtual inertia support and steady-state frequency secondary support is constructed; the power contribution of a fan under different time scales can be controlled by detecting the frequency change rate of the system; an additionalfrequency secondary support control strategy establishes a function relationship between a fan virtual inertia coefficient and system frequency sensitivity; the method dynamically responds to the full-time-scale frequency requirement of the system, achieves the power grid transient state and steady state comprehensive frequency expectation control performance under the wind power high permeability, improves the safe and stable operation level of a power grid, provides double-frequency support for the power grid under the transient state/steady state full-time scale, and further guarantees thesafe and stable operation of the power grid and a unit.

The increasing global energy and environmental problems are encouraging to the development and utilization of renewable and clean energy in various countries. Wind power is one of the major source in large-scale renewable energy applications. However, the frequency regulation becomes a critical issue while the technology is spreading. Research on the frequency modulation (FM) technology of wind turbines and its control strategy for future power grids become significant. The paper proposes a novel coordinated frequency control strategy with the synchronous generator to solve the unmatched state between the output power of the doubly-fed wind turbines (doubly-fed induction generators) and the grid frequency, combined with the frequency response characteristics of the synchronous generator. The FM coordination strategy is formulated by the modulation coefficient from current wind speed and operation mode of each wind turbine. By coordinating the FM output of the doubly-fed wind turbine and the synchronous generator within the allowable range of frequency deviation, it will achieve the dual goal of reducing the frequency regulation pressure of the synchronous generator and indirectly reducing the abandoned wind volume of the wind turbine. The simulation is carried out on the MATLAB/SIMULINK platform. The results show that the presenting variable coefficient frequency modulation strategy could significant smooth the wind power fluctuation, and allow the reserve power of the doubly-fed wind turbine can fully engaged in frequency modulation which will reduces the frequency modulation pressure of the synchronous generator in the system.

The peak load regulation ability of thermal power unit is closely related to the deep peak load regulation mode of thermal power unit and the peak load regulation strategy of power system. Meanwhile, the deep peak-load regulation ability is affected by many factors. In order to meet the increasing demand for peak load regulation, it is necessary to study the economy of deep peak load regulation of thermal power units under the condition of large-scale wind power grid connection from the perspective of thermal power enterprises, wind power enterprises and society. In this paper, taking full account of the current deep peak load regulation capacity and coal consumption cost control strategy of thermal power units, considering the economy of the deep peak load regulation stage of thermal power units, a unit combination optimization model with the joint constraint of "deep peak load regulation and coal consumption" is established, and the coordinated operation scheme of each thermal power unit after the wind power unit is connected to the system is arranged as a whole.

Converter transformer bushing as a piece of important power equipment in HVDC transmission, need to withstand AC voltage, DC voltage, and polarity reversal voltage during operation, the complexity of the operating conditions leads to high requirements on the insulation performance of the converter transformer bushing. The dry-type SF 6 gas-insulated DC bushing meets the requirement of no oil in the valve hall, is the bushing of the current mainstream converter transformer, and it uses SF 6 gas as the upper additional insulation. Analyze the electric field distribution in SF 6 gas of converter transformer bushing under different voltages, Especially important for the design of SF 6 gas internal voltage equalization device. This paper selects ±400kV dry-type SF 6 gas insulated bushing as the research object, establishes a simulation analysis model, and uses the finite element analysis method to calculate the electric field intensity distribution of the converter transformer bushing under different voltages. Mainly analyze the distribution law of electric field intensity in SF 6 gas. The results show that under DC excitation, the distribution of equipotential lines in SF 6 gas is relatively concentrated, and the electric field intensity near the top of the capacitor core is the highest. Under the condition of polarity reversal, the electric field intensity in SF 6 gas showed a downward trend.

Sub-synchronous oscillation may occur when the wind-thermal-bundled system sent out via AC/DC transmission (WTBH) is integrated in power grid. Causing large-scale wind-turbine tripping, even lead the system to collapse. First, in this study the mechanism of sub-synchronous oscillation of this system is analysed. Second, the influencing factors such as the ratio of the wind-thermal-bundled installed capacity, the series compensation parameters of AC transmission line, the different operating conditions of wind power etc., are analysed, which can cause different degree impact on the sub-synchronous oscillation. Finally, the system is simulated under the Power Systems Computer Aided Design (PSCAD) environment. The results show that under the same conditions, the higher series compensation, the greater transmission capacity of the AC line, the greater risk of the sub-synchronous oscillation. Under the condition of full load, the greater proportion of installed capacity of Doubly fed Induction Generator (DFIG) is, the less risk of sub-synchronous oscillation; Under the lower wind speed condition, reducing the number of wind turbine can eliminate the risk of sub-synchronous oscillation, and the oscillation frequency vary with the number of wind turbine.

Aiming at meeting the requirement of balancing the fluctuating wind power, this study proposed an optimal control strategy for wind power hybrid energy storage system considering output power amendment. Firstly, fluctuant wind power is decomposed into low-frequency, sub-high frequency and high-frequency components. Low-frequency part is used as the expected value of wind power integration. Sub-high frequency and high-frequency components are used as the target value of output power of storage batteries and ultra-capacitor energy storage system. Secondly, a double power amendment is proposed. In the first-time power amendment, the amendment coefficient is calculated by fuzzy controller whose inputs are the target value of power and state of charge (SOC) of the energy storage system. On the other hand, complement of batteries and super-capacitors are utilised in the second amendment. Through simulation analysis, it can be indicated that the configuration of the hybrid energy storage system and the control system design are feasible. This system can be widely used in wind farm, undertaking the task of balancing the fluctuating wind power.

Dividing wall column (DWC) was used to separate the system (1,2-propylene glycol + 1,3-butanediol + 1,4-butanediol). No research in a DWC has focused on such systems which were difficult to be separated for their great similarity in both molecular structures and properties. The rigorous steady-state and dynamic simulations, as well as the optimization of DWC alternative were performed with Aspen Plus and Aspen dynamics. Sequential quadratic programming (SQP) optimization method and the efficient sensitivity analysis tool were used to minimize the total reboiler and condenser duties. Moreover, a flow rate-composition cascade control structure was first developed to maintain targeted product purity under various external disturbances as feed flow rate and side product composition changed. DWC was compared with both a side rectifier configuration and conventional two-column distillation sequence in energy requirements and total annual costs (TACs) with the same number of stages. It showed that the energy requirements and TAC by DWC were reduced 47.60 % and 35.40 % respectively, compared with conventional distillation sequence, energy savings of 48.00 % and 34.11 % lower TAC compared with side rectifier configuration. This study provided a potential solution for the distillation of the systems with similar molecular structures and properties in a DWC.

Numerical calculation method on vibration of winding is researched in this paper. The 3D electromagnetic-structure model for a type S-11-M-500/35 transformer is established based on multiple physical fields coupling method. Firstly, the 3D- electromagnetic field of the transformer in the rated load current condition is established, the current, magnetic flux density and electromagnetic force of transformer are calculated. Calculated results of the electromagnetic force are coupled to the 3D structure filed model as force sources. Then, in order to analyze the transient vibration process of the transformer, the distribution of the vibration at different time and vibration curves in the 1/6, 1/2 and 5/6 positions of winding are calculated by considering the bolt preload and insulation block nonlinear characteristics. Finally, the vibration signal detection platform is built, load experiment test is made on the prototype, and the simulation results are verified by load tested data. The research method proposed in this paper can reflect dynamic characteristics of winding vibration accurately, which provides an effective method for further diagnosis on winding faults such as deformation and loosening caused by short circuit impact.

In the research of lightning protection in UHV substation, overvoltage will cause serious damage to the substation when the transmission line enters the lightning strikes. In this paper, combined with substation electrical main wiring, the UHV lightning transient characteristics of the module are considered. Then in the ATP-EMTP simulation environment, the GIS transient model of the key equipments such as pole tower, high voltage reactor and transformer are established under the lightning impulse. When the counterattack or the shielding failure strikes, the lightning intrusion wave overvoltage of a UHV substation GIS in different operating modes is calculated by comparing and analyzing the different types of arrester configuration. The results show that the outlet section and the high resistance share a set of arrester, and the main transformer installs a set of arrester to meet the equipment insulation margin requirement. The research results can provide reference for the arrester configuration of the station, and provide the theoretical basis for the lightning overvoltage protection of the UHV AC substation.

Through the analysis of the characteristics of most of rural indoor cable routing adopting wall concealed laying and there being more nodes in the lines, for the problems of leakage detection and location of rural indoor cables presenting small leakage current and different cable parameters in the same house, this paper designs a kind of handheld testing device with a certain precision and convenience. According to the magnetic field signal being generated by leakage current, inspection tour method is applied to leakage detection and location of rural indoor cable. The mathematical model of magnetic field generated by current carrying cable is established through Biot-Savart's Law. It is to calculate the size of a magnetic field generated by the leakage current. The leakage points are located by using the magnetic field signal's differences before and after it. Applying MULTISM simulation verifies the feasibility of the signal processing circuit. Set up the testing platform, and measure the magnetic field generated by the current of less than 30mA, and further verified the feasibility of the analog circuit.

This paper presents a power coordinated control strategy based on the maximum power point tracking (hereafter for MPPT) control, load power point tracking(hereafter for LPPT) and battery charging and discharging according to the relationship between the system energy flow and the operation condition of Wind-solar Systems with Battery Storage (hereafter for WSSBS), and the realization method was presented referring to practical data. We comprehensively construct stand-alone WSSBS and take the actual light and wind speed as the input. Finally, the feasibility of the power coordinated control strategy is tested under the condition of the random wind, the light intensity and the load in the MATLAB environment.

Electrical load simulator (ELS) is used for actuator performance testing on the ground. Disturbance torque is the key factor influencing test result. To improve ELS loading accuracy, this paper proposed an adaptive prediction control. This scheme predicts the trend of disturbance torque through the analysis of actuator position command. A compensation torque command is constructed by first differential and second differential of actuator position command. Its practical application shows that this scheme can reduce more than 90% of disturbance torque and can avoid system shock some extent.

The existing blind source separation algorithm has two problems for the separation of the vibration signal of the transformer. One is the uncertain number of the transformer vibration source. The other is the vibration measuring point, which is not sure after the signal separation. Aiming at these problems, this paper apply the Wavelet-SVD-Clustering analysis method on determinating the number of sources by using one single sensor acquisition of transformer tank vibration signal. The effectiveness of the method is verified by simulation and experimental data analysis. The method of this paper provides guarantee for the correct analysis and separation of the transformer vibration signal.

Based on mechanical load characteristics of opening and closing operations of 40.5kV vacuum circuit breaker, a new type of permanent magnet brushless DC motor operating mechanism is designed. The main structural sizes of the drive motor are calculated by using the target value method. Through analyzing the performance of the same volume motor under different winding wire diameter and number of turns, the scheme of winding wire diameter and turns — more output torque, faster motor rotational speed, higher power density — is determined. The overall design of the drive motor is completed. The mathematical model of the motor is established with finite element theory. The dynamic rotational angular displacement and output torque of the motor are obtained. Compared with the pre-existing motor operating mechanism, the volume of new drive motor is reduced by 23%, and the average output torque and rotational speed can be increased by 53.4 N·m and 38 r/m respectively.

This paper proposed demand-driven personalized product configuration design method. A variety of customer orders were clustered and fuzzy transformed; using ontology's feature to establish customer demand ontology model; in order to enable the product family to meet the dynamic demand of customers, established mapping relationship of customer demands and product family; using ontology to express product family model, achieved mapping of customer needs ontology and product family ontology, and improved efficiency of product configuration. Finally, we take planetary reducer as an example to demonstrate the feasibility of the method.

Extra-high (EHV) transmission system has the characteristics of high voltage and large capacity, and a high amplitude current will be generated through the grounding line and ground net when failure occurs. Step voltage caused by the diffusion of fault current in soil is an important parameter affecting the normal operation of the system. The calculation and analysis of the step voltage in IEEE Std 80-2000 standard is rough, unable to reflect the soil surface potential distribution in substation comprehensively. This paper present an algorithm combined transmission line theorem and finite element analysis to calculate the electric potential distribution accurately, getting the attenuation law of surface potential and the step voltage. Analysis shows that the soil surface electric potential is well-distributed in normal operation and the step voltage is very small, only a dozen volt; The potential value can achieve kilovolt during short trouble and there will be a great attenuation within one meter; Soil resistivity, earth current amplitude and buried depth of ground net are the important factors influencing the surface potential distribution and step voltage.

The insulation characteristic of high voltage circuit breaker in cold regions is the basis for the design of high voltage circuit breaker. In this paper, several gas of physical and insulated properties can be used in cold region circuit breaker are compares, CF4 gas was fed to use gas for cold region circuit breaker is obtained. Breakdown experiment of CF4 under typical electrodes was investigated, and the insulation performance of CF4 under short gap is obtained. The necessary basic data of CF4 mixed gas circuit breaker insulation and interruption performance research for cold region are provided.

Vacuum circuit breakers switch off shunt reactors, when the low voltage ride-through (LVRT) experiments are performed in Photo-voltaic (PV) system. Transient over-voltage is occurred and gotten a high amplitude in the experiments. It would cause external insulation breakdown of reactor and equipment damage. Base on circuit theory, this paper focused on factors which impacted on the transient over-voltage in the 35kV PV-LVRT experimental system. And then according to 35kV LVRT experimental line, a simulation model of experimental system was established in ATP/EMTP. The simulation results indicated that the closure value of vacuum circuit breaker the size of invested short-circuit reactance and the size of shunt capacitor were major influencing factors on the transient over-voltage caused by vacuum circuit breaker operation. A 0.1 μF shunt capacitor and a 100Ω shunt resistor could effectively reduce the peak value of transient over-voltage what were set to test point in the experiment.

According to the mechanical failure of Gas Insulated Switchgear (GIS) in the earthquake will cause a great loss to the power system. This paper, by using the three-dimension design software to build a geometric model of 420 kV GIS, by using the finite element analysis method to make the mode analysis, and then acquired structural frequencies and mode features of the GIS, and by using spectral analysis to get the stress distribution and structure deformation in the case of IX degree earthquake based on it. Through the simulation result of this model, the structure of the maximum stress occurs at the bracket where connected bus, and the maximum stress is 17.5Mpa that far less than the yield limit that is 235MPa. The maximum deformation occurs in the middle of the bus, and the maximum deformation is only 0.86 mm/m that comply with the requirements of the bus deformation is less than 3 mm/m. The results can provide a reference for the seismic reliability analysis of the high-voltage switchgear equipment.

A kind of monitoring and recording system of mechanical characteristics of high voltage circuit breaker is designed in this paper. The system that has the characteristic with microsecond single point acquisition speed and microvolt level amplitude resolution can collect information data of different mechanical characteristics of high voltage circuit breaker and automatic distinguishing data to fault category to establish the correct information and fault information database, and can monitor seven kinds of mechanical characteristics that include displacement, vibration, current of energy storage motor, current of opening/closing release coil, current of permanent magnet coil, voltage of permanent magnet coil of high voltage circuit breaker with the spring operation mechanism or the permanent magnet operation mechanism, and so on. The system can analysis time domain and frequency domain waveform with wavelet analysis method that have characteristics of multi-resolution analysis, and the ability of characterization the partial information of time domain and frequency domain signal for mechanical characteristics of high voltage circuit breaker. That make the target signal frequency division for removing high frequency noise to get pure signal waveform. The waveform can reflect trend of mechanical movement characteristics of high voltage circuit breaker accurately and clear.

When circuit breaker repeatedly breaks small capacitive current of compensation equipments,serious burning loss phenomenon is placed on the surface of static arc contact, which will lead to changing of contact shape. It may finally result in electric field distortion and adversely affect dielectric recovery characteristic. The mathematical models of electric field and flow field have been established in 126 kV SF6 circuit breaker. According to gas breakdown criterion of the streamer theory, dielectric recovery characteristic curves in the condition of burning loss angle θ=60° and no-burning loss have been researched. Then electric field distributions in various burning loss angles have been calculated. Results illustrate that seriously impacts critical breakdown voltage,maximal reduction is 130% at the distance of 95 mm. Values of point A are increasing along with larger burning loss angles. Compared with non-burning loss, the value is 7.7 times higher in θ=80° when separation of contact is 17 mm.

This paper establishes a model for the conductivity of non-equilibrium dual temperature arc plasma during small capacitive current interruption in a SF6 circuit breaker. Considering the contributions of electron-ion-neutral particle collision frequency and collision cross-section, we obtain the conductivity of SF6 plasma as a function of temperature and pressure and establish a dynamic arc model for small capacity currents. Based on the model, a numerical simulation is performed on the flow field with a load of small current of 1600 A for a 126 kV SF6 circuit breaker. Density, pressure and temperature distributions inside the circuit breaker chamber are obtained. With the electric field inside the same interrupter, dielectric recovery characteristic curves are described. In addition, the effect of arc duration on the dielectric recovery characteristics for small capacitive current is studied and the influence mechanism is discussed.

In order to improve the lightning calculating accuracy of transmission lines, the impact of surge corona is considered in this paper with the software of Electromagnetic Transient Program (EMTP) and a new improved corona model is proposed. The model is based on the concept of corona's radius. The region between the transmission lines which are under lightning and the ground is divided into corona region and no corona region. The analysis of lightning transient process shows that the influence of the corona is so great that the corona's impact should be taken into account to determine the insulation level. Besides, the effect of the power frequency voltage and the velocity changes are also studied. The simulation results show that considering the power frequency voltage and the smaller velocity due to the surge corona, the voltage of the top of tower is much higher than ignoring them, so these factors should be integrated when determine the insulation coordination for the transmission lines.

he temperature rise of GIS disconnector is a fatal factor that affects the power grid service performance. In this paper, a three-dimensional Finite Element Analysis model is established to analyze the magnetic-thermal field of disconnector cabinet. The distribution of magnetic field intensity and the values of eddy currents are calculated in the magnetic field first. Then the eddy current loss is coupled into the fluid-thermal field as a heat source to acquire the temperature rise value. Experimental values prove that this FEM model offers accurate results. So that the calculation method can be applied in the calculation of Magneto-Thermal Fields and the accurate parameters for product design and shorted the design cycle are provided.

A novel motor operating mechanism is presented which applied in the high voltage circuit breaker. The new motor is a permanent magnet motor with limited angle and only working in the starting stage. Based on the operation requirement of high voltage circuit breaker, the structure and parameters of motor are designed, including the rotor and stator structure, electric load, magnetic load, number of pole pair, air-gap, pole-arc coefficient and etc. The magnetic field analysis and dynamic simulation of motor operating mechanism is achieved by employing the finite element method. The dynamic parameters of motor, such as the torque, current, speed and location is obtained. Finally, the opening and closing stroke curve of moving contact is obtained through the performance testing with the circuit breaker. The results indicate that the motor operating mechanism have a good mechanical characteristics and reach the operation of high voltage circuit breaker.

A limited angle three-phase permanent magnet brushless DC (BLDC) motor operating mechanism for the 126kV high voltage vacuum circuit breaker is proposed and designed. The simulation model of motor operating mechanism is established by using the transient finite element method in according with the counter-force and the moment of inertia. The influence factors of the output mechanical characteristics is calculated and carried out, such as the rotor excitation structure, flux density, pole embrace, length-diameter ratio, turns-diameter ratio of the armature winding under the same poles etc. The simulation results indicated that the type of rotor excitation is employed the inset permanent magnet, which using the radial magnetization, the range of length-diameter ratio is 1.85 to 2.5, the pole embrace is bigger than 0.844, and the turns- diameter ratio of armature winding under the same slot is 14.28 to 23.7. So a larger air-gap flux density about 0.9T can be obtained, and the output mechanical properties parameters (such as output torque, speed and angle) meet with the requirement of circuit breaker.

In order to improve the performance of circuit-breakers, the influence of different magnetic materials on permanent magnetic actuators'(PMA) exciting current and operating characteristics are researched, and the finite element method(FEM) is used to establish the electromagnetic-mechanical coupled model. The electromagnetic equation, electrical equation and motion equation are solved to study dynamic characteristics of PMA. The yoke iron of PMA is made of cold-rolled silicon steel sheet and electrical pure iron respectively, the curves of the PMA parameters changing with time are obtained. The results show that the PMA with cold-rolled silicon steel sheet has better speed performance and less eddy current loss. A vacuum circuit-breaker with cold-rolled silicon steel sheet PMA is carried out, and in the corresponding experiments the operating characteristics are measured and the exciting current curves are also obtained. It is confirmed that the simulation results are accurate and have a certain actual significance.

As the standard equipment of the commercial aircrafts, air-ground data link system is widely used in modern aviation transport. However, its validity was unsatisfactory in our testing, especially in error of transmission. In this paper, some influencing factors during air-ground data transmitting were analyzed from the signal transmission. Considering ACARS was based on ARINC-618 protocol, a fundamental study in this article on transmission signal and demodulating signal of the ground air data link system was done on the basis of ACARS signal generated by the transient aircrafts. Keywords-ACARS, Very High Frequency (VHF), Signal Analysis

Leakage current that is strongly relative to the contamination flashover of outdoor insulators easily monitors online. In the paper, a BP Artificial Neural Network (ANN) model is proposed to predict the equivalent salt deposit density (ESDD) value based on the leakage current characteristics and environmental parameters which are both from artificial pollution tests. The contamination degree of insulators online monitoring is realized by using the proposed model. The data reflecting the relationship between the ESDD and the time is obtained from the natural contamination tests, and then the other ESDD prediction model is established based on the non- linear time series through analyzing ESDD time series properties. The second proposed model has high prediction precision, but in practical engineering, the data of ESDD can be obtained is very limited and need to be measured under a power outage condition. In order to get the better precision and practicality of the prediction, a new combination forecasting model is built, which the ESDD nonlinear time series prediction model is a correction model for the ANN model. The combination forecasting model is verified by part of experimental data, and the results show that higher precise online monitoring of contamination degree of insulators is achieved, the error is within ±4.3% and the prediction precision is 54% higher than that of the ANN model.

A novel risk forecasting model of high voltage circuit breaker insulation based on double artificial neural networks is proposed in the paper by analysis of the relationship between ESDD, flashover voltage and environmental factors. The data used to build the forecasting model is obtained from artificial pollution test. The proposed insulation fault risk forecasting model calculates the insulation fault probability under given environmental factors. Results of artificial pollution text indicate that the forecasting of this method is satisfied to practical application and useful to theoretical research.

To improve the accuracy and speed of fault current computation, a variable step size window length adaptive algorithm based on the adaptive filtering theory is proposed in the paper. Digital signal processing algorithm is one of the most important factor for the current protection algorithm. The paper analyzes the principle of the proposed algorithm and the way how to vary the step size and window length. The proposed adaptive algorithm can change the step size of the length changeable window in the filtering algorithm. It is sensitive to fault signals and has a fast response speed, and also have a more efficiently performance. The results of simulations show that the algorithm possesses good performance and is suitable for realizing the fast current protection function to the intelligent high voltage circuit breaker. According to the definite criterions to choosing the fault line, both theoretical analysis and simulation results show that the method has satisfactory reliability and sensitivity.

In order to study the effect of pollution un-uniform distribution on insulation performance of outdoor insulators, in the paper, the size of the dirt layer conductivity is used to describe the pollution extent of insulators and then the three-dimension harmonic quasi-static electric field of XP-160 insulators under pollution un-uniform distribution is calculated. The effects of different conductivity of dirt layers and several typical pollution un-uniform distributions to the electric field distribution along the surface of insulators are investigated. Comparing the leakage current obtained from artificial contamination test with the results of calculation, the reliability of the model is verified.

The structure and parameters of the motor used in the operating mechanism is designed according to the characteristics requirement of disconnecting switch. The two kinds of stator winding structures, one of which is stator winding symmetric distribution and the other one of which is stator winding asymmetric distribution, are proposed in the motor design. The dynamic simulation is achieved by using the finite element method according to the two kinds of stator winding structures. The simulation results verify the reasonable of motor design and gain the characteristic curves (torque, current, revolution and angle, etc.). The analysis results indicate that both of the two stator winding structures motor have an excellent performance which can give a sufficient opening or closing speed to meet the requirements of disconnecting switch.

The mechanical properties monitoring system of permanent magnet motor operating mechanism is developed base on the indoor 40.5kV vacuum circuit breaker in order to improve the security and reliability of power system. The high-precision linear displacement sensor is used to measure the stroke of moving contact, the angular sensor is employed to test the rotation angle of motor, and the hall current sensor is fit for detect the current of armature winding. The digital signal processor (DSP) is designed as the core of the monitoring system and the detection methods of mechanical characteristics are analyzed by considering the principles of the sensor and the signal translation circuit The mechanical parameters of circuit breaker are gained through debugging and running, which it can achieve the function of high precision real-time monitoring of circuit breaker and provide a data platform for the control of operating mechanism in the next step.

The permanent magnet motor, which is applied in the high voltage disconnecting switch, used for reducing the VFTO in the operation of disconnecting switch and enhancing the operating performance, and therefore achieves the opening and closing operation and brings quicker response ability and control performance, is presented. The structure and the parameters of the motor are designed according to the characteristics requirement of 550kV GIS disconnecting switch. The dynamic mathematical model of the motor is developed and the dynamic performance is carried out by using the transient finite element method. The simulation results verify the reasonable of motor design and gain the characteristic curves. The analysis results indicate that the permanent magnet motor have an excellent performance in the sense that it gives an opening or closing speed that meets the requirements of the disconnecting switch. Furthermore, it serves to provide a theoretical base for designing that permanent magnet motor applied in disconnecting switch.

As a important mechanical parameters for the vacuum circuit breaker, the contact bounce affects the electrical life of arc chamber. First, the mathematical model of contact bounce are established, the characteristics curve of contact bounce is obtained according to the mathematic model by using MATLAB. Secondly, the harm of contact bounce and the influence factors of contact bounce are analyzed. Finally, some methods are put forward to reduce the contact bounce, it has certain reference function on improving the design of vacuum circuit breaker in the future.

To improve the effect of existing inter-area oscillation control system in wide area network and multi-Agent system, the paper presents the control collaborative model of the inter-area oscillation based on multi-Agent and PMU for solving the problems presently such as centralized control and delay of wide-area power system in the control mode of the inter-area oscillation. It designs the monitoring strategies of three-level PSS signal, presents the collaborative process of suppressing the inter-area oscillation based on this model, and finally indicates the feasibility and effectiveness of the constructing the inter-area oscillation control system based on multi-Agent system by the digital simulation.

To solve the problem of the flashover risk assessment of contaminated insulator, a GIS-based region power grid polluted flashover precaution system is proposed in this paper. This system consists of two prediction models that the first is used to estimate contamination condition of insulator and the second is employed to forecast the probability of the flashover in complex weather conditions. The outdoor insulation level of operation insulator can be real-time mastered by using this system, which achieve the accurate flashover prediction and precaution. Then a technical support platform based on GIS is supplied in order to timely avoid the region power grid flashover accident. It is of important practical significance and application value for power grid disaster prevention and reduction.

This paper firstly analyzes the main measurement algorithm of synchronous phasor, then introduces the existing measurement method. The recursive fourier algorithm calculation quantity of which is less, is introduced by traditional DFT algorithm. This kind of improved discrete Fourier algorithm is obtained through the relative transformation, and this paper proposes a kind of frequency measurement method.

The grey theory is employed to establish the grey prediction-wind speed Weibull distribution model and calculate the Weibull distribution parameters according to the randomness and intermittence of the wind power output. The wind speed distribution of the wind farm and the effective wind power density are predicted accurately, the wind power and the electric fan efforts in generating capacity and other important data can be obtained according to the actual terrain wind farm wind speed data.

Considered the optimum arrangement scheme of PMU in a region of electric network, this paper primary introduced the definition of voltage stability's weak nodes and their region through a tidal current emulation and calculation method. The optimum arrangement scheme of PMU in electric network was also given. The Least-square procedure method was used in solving the equivalent resistance, which completed the weak node's dynamic voltage stability evaluation. The estimative accuracy of the scheme has been indicated according to the result of simulating test, which presents a theory method lying the foundation for the dynamic voltage stability evaluation of wide region electric power network.

To improve the operating characteristics of disconnector, a limited rotating angle permanent magnet motor actuator is presented in this article. The mathematical relationship between the moving contact stroke and rotation angle of motor is obtained by analyzing the dynamical coordination characteristics of motor actuator used in 550 kV gas-insulated switchgear disconnector. The electromagnetic field equation of motor, motive equation of rotor, and circuit equation of winding are solved simultaneously for acquiring dynamical characteristics of motor. The electromagnetic-mechanical coupled calculating model of motor is established by finite element method, and magnetic saturation of stator tooth is calculated and analyzed. According to the operating principle of motor, the double-closed control system which collects the motor speed and contact stroke signal during the operation of disconnector is developed. The experimental results show that the opening and closing speeds of disconnector are 1.1 and 1.2 m/s, respectively, which meet design requirements. The speed-regulating operation of disconnector is also carried out so that the switching speed of disconnector can adjust by motor actuator and control system.

The frequent appearance of switching disconnecting link in the electrical system leads a very large economic loss. A design of on-line monitoring system against ground wire based on GSM (global system of mobile communication) and SMS (short message service) was introduced in this paper. The configuration of the system, operating principle, the construction of the hardware, and the software design etc, were also given. This system realizes remote data communication and the real-time monitoring of ground wire site terminal. (4 pages)

On extra-high-voltage (EHV) power transmission line, the secondary arc influence to power system can't be ignored. The secondary arc is a key factor for success of single-phase auto reclose. The amplitudes of secondary arc current and recovery voltage are two decisive factors to extinguish secondary arc. High speed grounding switch (HSGS) is one of the important electric equipments, which is applied to the power system gradually. HSGS can not only earth when power system is fault, but also extinguish secondary arc current rapidly and reduce recovery voltage. This paper bases on the characteristic of secondary arc in 750 kV system, develops a sort of HSGS. This paper mainly studies the system of contactor of HSGS; calculating pressure, electric dynamic of contactor and the open distance. Finally, the whole mentality of design and the integral structure map of HSGS are shown. (5 pages)