分布式可再生能源的广泛接入对配电网的规划与运行产生重大影响,如何准确评估配电网的最大并网能力是一个配电网规划中的重要问题。该问题的最大挑战是在评估模型中如何刻画分布式电源出力的不确定性,并进行有效求解。为此,提出了一种基于机会约束的配电网分布式电源容量评估方法。该方法考虑了分布式电源出力及负荷预测的不确定性,将约束构建为线性机会约束形式。通过假设预测误差服从各个变量的边际分布相互独立、均值为0的概率分布,进一步将该机会约束模型转化为可被有效求解的混合二阶锥规划模型。最后,基于IEEE 33节点配电网络的算例给出了所提出方法的评估结果。基于文中提出的分布式电源容量评估方法在给定约束越限概率下可得到较大容量的接入方案。

基于电压源型换流器的多端直流输电电网是解决可再生能源并网和消纳的有效途径,因此研究交直流混合电网的潮流算法很有必要。提出了一种基于扩展节点法的交直流混合电网统一潮流算法。首先建立了电压源型换流站的稳态模型和控制策略及基于扩展节点法的交流和直流电网的网络模型。然后推导了基于牛顿法的统一潮流算法,将交直流混合电网的节点注入电流、支路电流和节点电压作为未知变量同时求解。通过IEEE 30节点交直流混合电网算例验证了所提算法的有效性。

For the difficulties of dynamic power quality control in substation, a compensationplan is presented in which cascade distribution static synchronous compensator(D-STATCOM)and switching capacitor work together. The method realizes the simultaneous compensation steady state for voltage regulation and impact load harmonics and reactive power. According to the application example ,a completeD-STATCOM system testing and commissioning method is put forward,including the regular inspection, insulation test, protection test ,reactive powerregulating range and output harmonic test,responding time test,steady state voltage regulation test,loss test and load compensation test. The detailed test data are given as well .Theexperience and conclusion of the project provide reference for the design and application of similar equipment.

A relocatable cascade distribution static synchronous compensator(D-STATCOM) is presented to meet the power quality requirement of distribution network when impulse loads connecting.Operating with switching capacitor branch,the compensator realizes the synchronous compensation of reactive power.As the example of the application in Jiangxi power grid,the compensation requirement of electric arc furnace which is typical impulse load was analyzed.With field wave recording data and distribution system parameter,simulation model was built.By using frequency dividing coordination control method,the active power compensator can work with switching capacitor branch perfectly.It reduced the dynamic capacity requirement of the compensating system effectively.The active power compensator realized moveable by accepting the cascade main circuit and modularization design.The field application plan of the equipment was put forward.The system parameter configuration method and principle were also given in detail.The operation effect shows that with the fast responding speed and working stability,the equipment can meet the compensation requirement of Var shock in distribution network.

DG based on Photovoltaic System Generation (PVS) has the probabilistic output power relied on natural conditions, the traditional deterministic load flow is not a suitable tool for the analyzing and maintaining distribution system. Aiming at this problem, this paper applies a probabilistic power flow (PLF) method to evaluate the influence of distributed generation with PVS. Firstly, the probabilistic model of PVS is established, Secondly, instead of the conventional Gram-Charlier expansion, the model of combined cumulant and Cornish-Fisher expansion is applied to calculate the PLF. This model has the more convergence for on-Gaussian probabilistic density function. Lastly, the IEEE 34 distribution system with the modification by injecting the PVS to some nodes is tested. The results show that the method in this paper is efficient and reasonable.

The main factors are found out for planning DC links terminating at AC system locations from the point of interactions between AC and DC systems, such as Short-Circuit Ratio (SCR), Voltage Static Indicator (VSI), and the power losses of the whole system. Based on the linear weighted summation method for multi-objective decision-making problems, a new method is proposed in this paper to select the stable and economic AC bus as the locations of DC links. By normalizing the factors, and calculating the weighted value, the chosen bus will be the one which both considers the stability and economy. Numeric tests show that the method presented in this paper is effective and feasible.

The design and application method of relocatable D-STATCOM are presented for distribution network power quality control purpose.Without transformer,the main circuit based on cascaded H-bridge inverter is used in the method.The compensation principle is analyzed according to a mathematical model.The parameter design of cascaded unit is based on the calculation of connecting voltage level and the equipment capacity.The optimal economic capacity is another important factor which should be considered during parameter design.Compact design of the compensator is implemented by using level power electronics unit of the power module.The inverter cabinet design is based on stratified and sub-phase principles.With these methods the whole system is integrated in a container to facilitate movement of the device.As an example of its application in Jiangxi power grid,the detailed parameter configuration of the relocatable D-STATCOM is given.By implementation of hierarchical classification protection method and the frequency divided control method which combines phase-shift SPWMs,the effectiveness of the proposed method is validated with satisfactory results.

The invention provides a capacity configuration method of an energy storing device for regulating and controlling the synchronization of a distributed photovoltaic power supply, which comprises the following steps: actually measuring an actual output power curve P(t) of the distributed photovoltaic power supply in a day; acquiring an ideal output power curve P*(t) of the distributed photovoltaic power supply in a day; determining permitted output error alpha of the photovoltaic power supply; carrying out discretization disposal on the P(t) and the P*(t) to obtain the corresponding P(k) and P*(k), wherein K is equal to 0, 1, 2, ..., N; calculating the upper ideal output error power Pu*(k) and the lower ideal output error power Pd*(k); calculating charging electric energy Wc needed by the energy storing device; calculating the discharging electric energy Wf needed by the energy storing device; calculating the corresponding Wc and Wf under the three typical meteorological conditions of a sunny day, a cloudy day and a rainy day; comparing Wc with Wf obtained by calculating under the three typical meteorological conditions of a sunny day, a cloudy day and a rainy day; and taking the maximal value as the capacity of the energy storing device. The method of the invention is suitable for the reasonable configuration of the energy storing device for regulating and controlling the synchronization of the distributed photovoltaic power supply.

The paper compared digital substation and intelligent substation as well as presented index evaluation system of intelligent substation pilot project.Moreover,matters in intelligent construction such as location,idea,principle,technique standard,related technology and management were discussed to provide reference for intelligent substation pilot project.

针对冲击性负荷工作的时段性特点,配网静止无功发生器D-STATCOM要在电力系统中推广应用必须同时具备冲击性负荷补偿和稳态调压的功能.为实现这一目的,提出一种适合于变电站应用的D-STATCOM综合控制方法.先通过冲击性负荷工作状态判断,确定采用稳态调压还是负荷补偿控制方式.若采用稳态调压方式则通过与变电站投切电容支路形成良好配合,实现限值范围内的电压调整.若采用负荷补偿方式则通过实时的限值判断确定无功与各次谐波电流的补偿重点,以基于瞬时无功功率理论的电流检测方法为基础,结合直流侧电压的直接PI控制算法和补偿电流的增量迭代式广义积分控制算法实现基波与各次谐波的分频控制.控制方法易于工程实现,D-STATCOM可实现多种功能,有利于提高装置的性价比.现场应用证明了装置的有效性.

According to Jiangxi economy and distribution network status,problems of distribution network were presented.Moreover,principle of distribution network suitable for Jiangxi as well as Jiangxi distribution network planning and construction scale was proposed.Finally,economic and social benefit was pointed out.

A new type of DC De-Icing system is presented for solving the problems of transmission line icing when ice disaster happens. The two sections of DC De-Icer and assistant decision-making platform are included in it. The DC De-Icer realizes removability by integrating the DC power in a tanksemi-platform trailer with modular design. The main circuit of the power is composed of six voltage sourced converter(VSC) modules, which combine chopper circuit. The control method of pulse width modulation(PWM) rectifying voltage regulation combined with constant current chopper and layered protection scheme are put forward to realize the stepless regulation of DC output current and stability operation. Based on the research of the DC De-Icing critical current and De-Icing time calculation model, DC De-Icing assistant decision-making platform is established with the combination of mini weather station. Served with DC De-Icer, the application of this platform will contribute to the increase of DC De-Icing efficiency and guarantee the safe operation of transmission line. As a integrated DC De-Icing plan, the system has been put into use in Jiangxi power grid. In view of DC De-Icer implement experience lack, the design and application method of this project will be good for the application of such kind of systems.

The smart grid research and construction are carried out in the worldwide. State Grid Corporation of China has programmed to establish the strong grid with the unified standards. Then the research and construction of intelligent substations has begun. The structure of intelligent substations is introduced in this paper in terms of definition,features and function. Also,the construction of the experimental intelligent substation is discussed. Finally,research and construction process are analyzed.

The future development trend of electric power grid is smart grid. The concept and function characteristics of smart grid are introduced in this paper firstly; then the progress of reserarch on smart grid home and abroad is issued,the different of the implement of smart grid home and abroad is analyzed. The ideas and suggestions about the construct of jiangxi smart gird are put forward and start further discussion in this paper,such as adaptation research,construct mode,the acceptable capacity of big scale wind power,microgrid and smart substation,etc.

On the basis of minimal path a reliability equivalent calculation with equivalence recursion is proposed.According to distance between load points and root node of feeders,the proposed method performs layer sorting for them,and based on layer-numbers of the nodes where loads locate their reliability indices are stepwise calculated.During the calculation of reliability of load points in each layer,the reliability equivalent circuit of all equipments located in this layer and upper layers is calculated and is used by following calculation procedures.Moreover,a concise Newton power flow calculation method using constant Jacobian matrix that is applied to radial power network is proposed to calculate the impact of transmission capacity on reliability of distribution system.Based on factorization method the network topology of radial power network and the topology of factor graph are analyzed and it is proved that they two topologies are the same,on this basis a Newton power flow algorithm that possesses similar program to branch-oriented forward/backward sweep algorithm is developed.This algorithm is easy to be programmed and implemented and converges as fast as traditional Newton method.Case study results show that the proposed reliability evaluation algorithm is efficient.

On the guideline of the Guiding Opinions on Training Base Construction ordained by the State Grid Corporation, this paper proposed a scheme for promoting the construction of training base for dispatchers.Based on analysis of the staff status in Jiangxi power dispatch center and optimization of the existing dispatch-training resources, the construction scheme of dispatch-training base for Jiangxi power grid was discussed in the paper, which included the building of general dispatch-training room, corresponding training evaluation system, information management platform, and so on.The scheme in this paper can provide beneficial references for other provincial grid corporations in the process of dispatch-training base construction.

The function of static state security analysis for the traditional energy management system (EMS) is enhanced, and a static state security early warning and preventive control subsystem is designed and implemented. The subsystem can evaluate power system operation’s security level and identify insecure cases in real time. Further more, countermeasures for the insecure cases are also given. The problem of power flow unsolvability due to heavy load for certain contingencies, which represent the most severe cases, is investigated. Based on the minimum mismatch function and successive linear programming method, a practical algorithm is developed to restore power flow from unsolvability. A digital simulation on an actual provincial power system is made to demonstrate feasibility and applicability of the method proposed. The method proposed has been embedded in an early warning and security countermeasure system running in a control center of a provincial power grid.

The generator bidding in oligopolistic electricity market is studied with optimal control theory.The repeated bidding process in electricity market is modeled as a dynamic feedback system.A standard optimal control problem is formulated to explore the generator's long-term/multi-period optimization behavior.The periodic property of the system demand is taken into account in the formulation.Based on the necessary conditions for optimality via Pontryagin maximum principle,a specific sweeping method is adopted to derive the optimal state-feedback control rule.Simulation studies show the performance of optimal control for solving the problem of generator bidding.

对线路覆冰导致电力杆塔倒塌的原因进行了简要分析,并对今后线路的运行维护和建设提出了一些建议。

Several network connection-based visualization methods including the surface, bars, pipes and animated arrows are designed to express point and line data in power system control centers. Common visualization topics are proposed. The spatial interpolation algorithm in surface plotting is improved and the application of color-mapping is discussed. Based on an existing EMS 2D graphics platform, a 3D visualization software module is designed and developed, which has the features of rich display forms, good real-time performance, cross-platform implementation, and easy integration with other systems. This module has been put into operation in several power system control centers with the real-time effect and performance presented.