Abstract: A reactive power optimization method for integrated transmission and distribution networks related to a field of operation and control technology of an electric power system is provided. The reactive power optimization method includes: establishing a reactive power optimization model for a transmission and distribution network consisting of a transmission network and a plurality of distribution networks, in which the reactive power optimization model includes an objective function and a plurality of constraints; performing a second order cone relaxation on a non-convex constraint of a plurality of distribution network constraints of the plurality of constraints; and solving the reactive power optimization model by using a generalized Benders decomposition method so as to control each generator in the transmission network and each generator in the plurality of distribution networks.

Abstract: The present disclosure relates to a method and an apparatus for controlling a voltage in a near direct current area. The method includes: collecting measured values of parameters as initial values of prediction values of the parameters; inputting the initial values into a preset control model for optimizing a model predictive control; solving the preset control model to obtain a solution sequence of the terminal voltage setting values of the generators participating in the voltage control within a time window; and sending first values in the solution sequence to the generators, such that the voltage control in the near direct current area is realized.

Abstract: The present disclosure relates to a method and an apparatus for controlling a voltage in a wind farm. The method includes: collecting measured values of parameters as initial values of the prediction values; inputting the initial values into a preset control model for optimizing a model predictive control; solving the preset control model to obtain a first solution sequence of the reactive power setting values of the wind turbines and a second solution sequence of the terminal voltage setting values of the static var generators; and sending first values in the first solution sequence to the wind turbines and first values in the second solution sequence to the static var generators, such that a voltage control in the wind farm is realized.

Abstract: The present disclosure provides a method and a device for controlling a distributed generator in a distribution system. The method includes: extracting a first statistic feature of a load at each bus; extracting a second statistic feature of a distributed generator at each bus; establishing a probability distribution set of each first and second statistic feature; determining security constraints of the distribution system; obtaining a bilinear matrix inequality constraint by using a C-VaR approximation algorithm and a duality algorithm based on the probability distribution set and on the security constraints; determining an objective function to maximize a total installed capacity of the distributed generators; solving the objective function according to the bilinear matrix inequality constraint to obtain an installed capacity of each distributed generator; and controlling an access of each distributed generator according to the installed capacity.

Abstract: The present disclosure relates to a method for primary frequency regulation of an electric network based on large building air conditioning loads cluster. The method includes the use of a two layer control structure with a central coordinating layer and a local control layer. Each local controller performs a thermal model parameter identification and a local air conditioning autonomous control, and uploads local information to the central controller at the end of each communication interval tgap, the central controller broadcasts coordinating information to each local controller. Based on the coordinating information sent from the central controller, each local controller determines whether a power deviation is beyond an action dead zone at the beginning of each action period tact, if beyond, then perform a frequency regulation control action, else, perform no action and estimate operation states of all the air conditionings at the beginning of the next action period.

Abstract: The present disclosure provides a frequency control method for a micro-grid and a control device. The method includes: determining a middle parameter at iteration k; determining a local gradient parameter at iteration k according to the cost increment rate at iteration k, the frequency difference between iterations k and k+1, and communication coefficients; performing a quasi-Newton recursion according to the middle parameter and local gradient parameter to acquire a recursion value; determining the cost increment rate at iteration k+1 according to the recursion value; determining an adjustment value of an active power according to the cost increment rate at iteration k+1; adjusting the active power according to the adjustment value if the adjustment value satisfies a constraint condition and judging whether the difference is smaller than a predetermined threshold; executing k=k+1 if yes and stopping the frequency control if no.

Abstract: A method and a device for estimating a state of a power system are provided. The method includes: dividing the power system into a plurality of sub-systems; establishing a first linear model of the power system for a first stage; solving the first linear model by an alternating direction multiplier method to obtain the intermediate state variables of each sub-system; performing a nonlinear transformation at a second stage on the intermediate state variables to obtain intermediate measured values; establishing a second linear model of the power system for a third stage according to the intermediate measured values; and solving the third linear model by the alternating direction multiplier method to obtain the final state variables of each sub-system.

Abstract: A method and a device for identifying a feasibility of a transmission interface constraint in an online rolling dispatching are provided. The method comprises: S1, establishing an online rolling dispatching model including a transmission interface constraint; S2, establishing a Lagrangian relaxation dual problem of the online rolling dispatching model; and S3, identifying a feasibility of the transmission interface constraint by solving the Lagrangian relaxation dual problem.

Abstract: A method for obtaining a continuous power flow of an electric power system is provided. The method uses the bus having the fastest voltage drop as the local parameterization bus, defines a slope of a line determined by the voltage of the geometric parameterization bus and the load growth factor as the parameterization variable, and adds a one-dimensional geometric parameterization constraint equation near turning points to obtain a nonsingular extended power flow equation, such that the continuation power flow can cross the turning points and a continuous P-V curve can be drawn reliably.

Abstract: The present disclosure provides a method and a device for controlling an active distribution network, relating to the field of power system operation and control technology.

Abstract: A method for obtaining a three-phase power flow of a power distribution network and a device for obtaining a three-phase power flow of a power distribution network are provided. The method includes steps of: selecting a three-phase power transformer in the power distribution network and configuring a secondary side of the three-phase power transformer with an ungrounded neutral connection, such that the three-phase power transformer satisfies a preset voltage-current relationship; adding a constraint condition to the preset voltage-current relationship to correct a three-phase admittance matrix of the three-phase power transformer; and applying the three-phase admittance matrix to a preset algorithm to obtain a three-phase power flow of the power distribution network.

Abstract: The present disclosure provides a robust restoration method for an active distribution network, which can be used under uncertain environment. For uncertain factors in the power restoration, the robust restoration method creates polyhedral uncertainty sets of the load demands and the distribution generation outputs and presents a two-stage robust restoration optimization model to obtain switching decisions under the worst-case fluctuation scenarios, thereby maximizing the restored power, while satisfying constraints and uncertainty budget. The robust restoration method uses the column-and-constraint generation algorithm to solve the robust restoration optimization model. The robust restoration strategies generated by the model can make sure restoration feasibility under any fluctuation scenarios in the uncertainty sets. Implementation of the method is simple and the method has practicability and can solve unfeasibility of restoration strategies caused by uncertain factors in the active distribution network.

Abstract: A method and a device for charging an electric vehicle in a power system are provided. The method includes: obtaining a plurality of electric vehicles connected to the power system at a dispatching time, and obtaining a rated charging power and a charging requirement at the dispatching time; determining a charging period corresponding to the plurality of electric vehicles; determining a forecast period, and obtaining a charging requirement, a remaining charging energy capacity and a maximum charging power; establishing a charging model of the plurality of electric vehicles, establishing a first constraint of the charging model, and establishing a second constraint of the charging model; and solving the charging model under the first constraint and the second constraint to obtain an optimal charging power of each electric vehicle at each charging time in the charging period so as to charge each electric vehicle under the optimal charging power.

Abstract: A method and a device for charging an electric vehicle in a power system are provided. The method includes: obtaining a first electric vehicle connected to the power system, and obtaining a rated charging power and a first charging requirement; determining a first charging period corresponding to the first electric vehicle; determining a forecast period, and obtaining a second electric vehicle to be connected to the power system; revising the first charging period to obtain a second charging period, and obtaining a second charging requirement and a maximum charging power; establishing a charging model, establishing a first constraint of the charging model, and establishing a second constraint of the charging model; and solving the charging model under the first constraint and the second constraint to obtain an optimal charging power so as to charge each first electric vehicle under the optimal charging power.

Abstract: A method and a device for controlling a local voltage are provided. The method includes: obtaining a first voltage value of a high-voltage side bus in a local transformer substation; determining a control strategy according to a starting threshold value for a voltage enhancement control, a starting threshold value for an under-voltage load shedding and the first voltage value of the high-voltage side bus; and performing the control strategy to control a charging power of an electric vehicle charging station corresponding to the local transformer substation, so as to control the local voltage of the local transformer substation.

Abstract: A security and economy coordinated automatic voltage control method based on a cooperative game theory is provided. The method includes: establishing a multi-objective reactive voltage optimizing model of a power system; resolving the multi-objective reactive voltage optimizing model into an economy model and a security model; solving the economy model and the security model based on the cooperative game theory to obtain the automatic voltage control instruction; and performing an automatic voltage control for the power system according to the automatic voltage control instruction.

Abstract: The present disclosure relates to a partition method and a partition device for a power system and belongs to a field of an evaluation and control of a power system. The method includes steps of: obtaining a quasi-steady sensitivity matrix according to generators participating in automatic voltage control and load buses in the power system; obtaining a power system model according to the quasi-steady sensitivity matrix and the load buses; determining principal component vectors and principal component singular values according to the power system model; determining a principal component vector dominated by each generator according to the principal component vectors and the principal component singular values; and partitioning the generators dominating a same principal component vector to a partition, and partitioning the load buses according to a partition result for the generators.

Abstract: The present disclosure relates to a method and an apparatus for controlling a voltage in a wind farm. The method includes: collecting measured values of parameters as initial values of the prediction values; inputting the initial values into a preset control model for optimizing a model predictive control; solving the preset control model to obtain a first solution sequence of the reactive power setting values of the wind turbines and a second solution sequence of the terminal voltage setting values of the static var generators; and sending first values in the first solution sequence to the wind turbines and first values in the second solution sequence to the static var generators, such that a voltage control in the wind farm is realized.

Abstract: A method and apparatus for controlling a reactive power of a generator in a power plant are provided. The method includes: S1, dividing a plurality of power plants into a plurality of plant-plant coordination groups; S2, dividing generators into a first generator and a second generator set; S3, calculating a deviation between a measured voltage and a preset voltage of a central bus; S4, comparing the deviation with a control dead band threshold; S5, establishing a reactive power tracking model if the deviation is greater than the control dead band threshold; S6, establishing a reactive power keeping model; and S7, obtaining sum reactive power adjustments of the generators according to the first reactive power adjustments and the second reactive power adjustments, and obtaining voltage adjustments of buses according to the sum reactive power adjustments.

Abstract: The present disclosure relates to a method and an apparatus for controlling a voltage in a near direct current area. The method includes: collecting measured values of parameters as initial values of prediction values of the parameters; inputting the initial values into a preset control model for optimizing a model predictive control; solving the preset control model to obtain a solution sequence of the terminal voltage setting values of the generators participating in the voltage control within a time window; and sending first values in the solution sequence to the generators, such that the voltage control in the near direct current area is realized.