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: 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 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: The present disclosure provides a method and a device for solving an optimal power flow in a power supply system. A second convex model of the optimal power flow is established. A relaxation variant sum e according to the second convex model is determined. It is judged whether the relaxation variant sum e is greater than a preset threshold. If the relaxation variant sum e is greater than the preset threshold, the second convex model of the optimal power flow is established. If the relaxation variant sum e is not greater than the preset threshold, the solution of the second convex optimal model is determined as a feasible solution of the optimal model of the optimal power flow.

Abstract: The present disclosure provides a dispatch method and apparatus for controlling a combined heat and power CHP system. The CHP system includes CHP units, non-CHP thermal units, wind farms and heating boilers; the CHP units, the non-CHP thermal units and the wind farms form an electric power system EPS of the CHP system; the CHP units and the heating boilers form a central heating system CHS of the CHP system; and the EPS and the CHS are isolable. The method includes: establishing a combined heat and power dispatch CHPD model, an objective function being a minimizing function of a total generation cost of the CHP units, the non-CHP thermal units, the wind farms and the heating boilers; solving the CHPD model based on Benders decomposition to obtain dispatch parameters for the EPS and the CHS; and controlling the EPS and the CHS according to the corresponding dispatch parameters respectively.

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: Disclosed are a method and a device for determining safe threshold for power grid voltage of a wind farm converging area, The method includes: obtaining ground state voltage; obtaining upper and lower limit voltage of the output bus, first lower and upper limit of reactive powers of fans and compensation devices, and lower and upper limit of active power fluctuations; obtaining second lower and upper limit of reactive powers of fans and compensation devices; determining whether voltage error is greater than a predetermined threshold; replacing the first lower and upper limit of the reactive powers of fans and the reactive powers of compensation devices with the second lower and upper limit of reactive powers of fans and compensation devices respectively, and repeating above steps if the voltage error is greater than the predetermined threshold, else defining the upper and lower limit voltage of the output bus as a safe threshold.

Abstract: The present disclosure provides a dispatching method and a dispatching device for an integrated transmission and distribution network. The integrated transmission and distribution network includes a transmission network and at least one distribution network. The method includes: establishing a dispatch model of the integrated transmission and distribution network, in which dispatch model includes an objective function and constraints, the objective function is a minimizing function of a total generation cost of the transmission network and the at least one distribution network under the constraints; solving the dispatch model to obtain dynamic dispatch parameters for the integrated transmission and distribution network; and dispatching the integrated transmission and distribution network according to the dynamic dispatch parameters.

Abstract: A voltage control method and apparatus of a central bus in a power system are provided. The method comprises: S1: obtaining a predetermined voltage and a current voltage; S2: obtaining a first voltage adjustment of the generator and a second voltage adjustment of the dynamic reactive power compensation device; S3: sending the first voltage adjustment and the second voltage adjustment; S4: judging whether a current reactive power of the dynamic reactive power compensation device is between a first predetermined reactive power and a second predetermined reactive power; S5: if yes, obtaining a third voltage adjustment of the generator and a fourth voltage adjustment of the dynamic reactive power compensation device; S6: sending the third voltage adjustment and the fourth voltage adjustment; repeating steps S1-S7 after a predetermined period of time; S7: if no, repeating steps S1-S7 after the predetermined period of time.

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.