Abstract: An online voltage control method for coordinating multi-type reactive power resources is provided. First, a linearized power flow equation of branch reactive power is established, and an online voltage control model of multi-type reactive power resources including an objective function and constraint conditions is constructed. The constrain conditions includes generator reactive power constraints, reactive power compensator constraints, transformer tap position constraints, a nodal reactive power balance constraint, and slack contained nodal voltage constraints. Then, an optimization result of voltage control is obtained by solving the model.

Abstract: The disclosure provides a method for planning a power distribution network, an apparatus for planning a power distribution network, and a storage medium. The method includes: establishing a model for planning the power distribution network, the model including a target function and constraints, the target function for minimizing a cost of the power distribution network when branches and nodes are installed into the power distribution network, the nodes including transformers and substations, the constraints including a power balance constraint of the power distribution network, a power constraint of the branches, a power constraint of the transformers, a radial operation constraint of the power distribution network, a fault constraint, a calculation constraint of indices of a reliability, a constraint of the indices of the reliability, and a logic constraint; and solving the model to determine whether the branches and the nodes are installed into the power distribution network.

Abstract: The present disclosure provides a stable region determining method for distributed cyber-physical power systems with multiple time delays, including: first establishing a state space expression of the cyber-physical power systems under distributed control with multiple time delays; converting the state space expression to frequency domain through Laplace transform to obtain a characteristic equation for multiple time delays of the cyber-physical power systems under distributed control, and establishing a marginally stable characteristic equation with unified time delay to obtain a marginally stable characteristic equation for multiple time delays of the cyber-physical power systems under distributed control with unified time delay; in each time delay direction, solving a stable boundary for time delay of the cyber-physical power systems under distributed control; connecting the stable boundaries for time delays in all time delay directions, and generating a stable domain for time delays of the cyber-physical

Abstract: A transient stability assessment method for an electric power system is disclosed. Transient stability tags and steady-state data of the electric power system before a failure occurs are collected from transient stability simulation data. Data sets under different predetermined failures are obtained based on a statistical result of the transient stability tags and a maximum-minimum method. A similarity evaluation index between different predetermined failures is constructed based on a Jaccard distance and a Hausdorff distance. Different predetermined failures are clustered based on a clustering algorithm. A parameters-shared siamese neural network is trained for different predetermined failures in each cluster to obtain a multi-task siamese neural network for the transient stability assessment.

Abstract: A natural gas circuit modeling method for operation control of an integrated energy system, including: establishing, based on the mass conservation and momentum conservation equations in the natural gas pipeline, as well as the state equation and the flow equation of the natural gas, a partial differential equation between the flow rate and the pressure in the natural gas pipeline; mapping the gas circuit to the frequency domain through Fourier transform and obtaining the lumped parameter model through the two-port equivalence; establishing, combined with the natural gas compressor equation, the general branch model of the natural gas circuit; defining the node-branch correlation matrix and the node-outflow branch correlation matrix to establish the topological constraint equation of the natural gas circuit; and establishing, combined with the general branch model of the natural gas circuit and the topological constraint equation of the natural gas circuit, the natural gas circuit equation.

Abstract: The present disclosure provides a temperature-responsive self-degradable temporary plugging agent and a preparation method thereof as well as its application in plugging the wellbore, which relates to the technical field of oilfield exploitation. The temporary plugging agent provided in the present disclosure includes preparation raw materials of the following mass percentages: monomer 4-6%, crosslinker 0.2-1%, initiator 0.02-0.06%, degradation catalyst 0.05-0.1%, chain transfer agent 0.01-0.05%, and the balance water. The temporary plugging agent of the present disclosure is liquid before gelling, with a low viscosity and a good fluidity, and easy to be pumped. When being pumped into the wellbore, the temporary plugging agent may crosslink at the temperature of the reservoir section, with good gelling properties. At the end of the operations, it can be degraded by itself, without drilling tools, with no need for gel breaking, and with no need for additional degradation promoters.

Abstract: The present disclosure provides a temperature-responsive self-degradable temporary plugging agent and a preparation method thereof as well as its application in plugging the wellbore, which relates to the technical field of oilfield exploitation. The temporary plugging agent provided in the present disclosure includes preparation raw materials of the following mass percentages: monomer 4-6%, crosslinker 0.2-1%, initiator 0.02-0.06%, degradation catalyst 0.05-0.1%, chain transfer agent 0.01-0.05%, and the balance water. The temporary plugging agent of the present disclosure is liquid before gelling, with a low viscosity and a good fluidity, and easy to be pumped. When being pumped into the wellbore, the temporary plugging agent may crosslink at the temperature of the reservoir section, with good gelling properties. At the end of the operations, it can be degraded by itself, without drilling tools, with no need for gel breaking, and with no need for additional degradation promoters.

Abstract: A method for dispatching a power grid is disclosed. The method includes: obtaining a whole power generation interval scheduled for a cluster of renewable energy stations from a power grid dispatching center; establishing a decomposition model that includes an objection function and constraint conditions; decomposing the whole power generation interval with the decomposition model to obtain each power generation interval of each renewable energy station; and controlling each renewable energy station to generate powers based on each power generation interval. The objection function minimizes a total operating cost in the power grid and includes a renewable energy randomness indicating an actual power generation amount of each renewable energy station.

Abstract: The disclosure relates to a two-side stochastic dispatching method for a power grid. By analyzing historical data of wind power, the Gaussian mixture distribution is fitted by software. For certain power system parameters, a two-side chance-constrained stochastic dispatching model is established. The hyperbolic tangent function is used to analyze and approximate cumulative distribution functions of random variables in the reserve demand constraint and the power flow constraint, to convert the two-side chance constraint into a deterministic constraint. The disclosure can have the advantage of using the hyperbolic tangent function to convert the two-side chance constraint containing risk levels and random variables into the solvable deterministic convex constraint, effectively improving the solution efficiency of the model, and providing decision makers with a more reasonable dispatching basis.

Abstract: A power grid reactive voltage control method and control system based on two-stage deep reinforcement learning, comprising steps of: building interactive training environment based on Markov decision process, according to a regional power grid simulation model and a reactive voltage optimization model; training a reactive voltage control model offline by using a SAC algorithm, in the interactive training environment based on Markov decision process; deploying the reactive voltage control model to a regional power grid online system; and acquiring operating state information of the regional power grid, updating the reactive voltage control model, and generating an optimal reactive voltage control policy. As compared with the existing power grid optimizing method based on reinforcement learning, the online control training according to the present disclosure has costs and safety hazards greatly reduced, and is more suitable for deployment in an actual power system.

Abstract: A method for estimating a state of a combined heat and power system is provided. The method include: establishing an objective function; establishing constraints under a steady-state operating stage; converting the objective function and the constraints by utilizing a Lagrangian multiplier to obtain a Lagrange function; obtaining a steady-state estimation result of the combined heat and power system based on the Lagrange function; calculating an energy transmission delay produced by each pipe; establishing a dynamic constraint of each pipe based on the steady-state estimation result and the energy transmission delay; converting the objective function, the constraints, and the dynamic constraint by utilizing the Lagrangian multiplier to update the Lagrange function; obtaining a dynamic-state estimation result of the combined heat and power system during a dynamic-state operating stage of the combined heat and power system based on the updated Lagrange function.

Abstract: The present disclosure provides a stability criterion for time-delay of cyber-physical power systems under distributed control, which relates to a field of cyber-physical power systems technologies.

Abstract: The present disclosure relates to a method, an apparatus and a storage medium for controlling a combined heat and power system, belonging to the field of power system technologies. The method discloses: establishing a decision model, the decision model including an objective function aiming to minimize a total cost of the first generators and the second generators, and constraints with respect to the first generators, the second generators and the heating exchange stations; solving the decision model to acquire operation states of the first generators, operation states of the second generators, and operations states of the heating exchange stations; and controlling the combined heat and power system, based on the operation states of the first generators, the operation states of the second generators, and the operations states of the heating exchange stations.

Abstract: A planning method for a power distribution automation system based on a reliability constraint is provided. The method includes: defining installation states of components and principles of a fault isolation, a load transfer and a fault recovery after a branch fault occurs; establishing a reliability evaluation optimization model for a power distribution network based on a mixed integer linear programming, the reliability evaluation optimization model comprising a target function and constraint conditions; solving the reliability evaluation optimization model to obtain an optimum planning scheme; and planning the power distribution automation system based on the optimum planning scheme.

Abstract: The present disclosure provides a stable region determining method for distributed cyber-physical power systems with multiple time delays, including: first establishing a state space expression of the cyber-physical power systems under distributed control with multiple time delays; converting the state space expression to frequency domain through Laplace transform to obtain a characteristic equation for multiple time delays of the cyber-physical power systems under distributed control, and establishing a marginally stable characteristic equation with unified time delay to obtain a marginally stable characteristic equation for multiple time delays of the cyber-physical power systems under distributed control with unified time delay; in each time delay direction, solving a stable boundary for time delay of the cyber-physical power systems under distributed control; connecting the stable boundaries for time delays in all time delay directions, and generating a stable domain for time delays of the cyber-physical

Abstract: A data-driven wind farm frequency control method based on dynamic mode decomposition. The method enables a low-dimension nonlinear dynamic feature of a wind power system to perform global capturing in a high-dimension space through a state transition matrix given by a Koopman operator theory, thus fewer data samples are necessary while control requirements are satisfied with respect to a model fitting accuracy. Meanwhile, a pure linear feature of a control model also provides a favorable foundation for fast on-line dynamic response, thereby satisfying response accuracy and speed requirements simultaneously in an actual control step.

Abstract: A method of assessing dynamic flexibility for a virtual power plant, which belongs to the technical field of operating and controlling a power system. The method equals a virtual power plant to an equivalent energy storage device and an equivalent generator and decouples a network constraint condition between the two types of devices through a Robust optimization method. Subsequently, by using a two-stage Robust optimization algorithm, parameters of the equivalent energy storage device and the equivalent generator are calculated and finally accurate depiction is realized on adjusting ability of a distributed resource, so as to provide a scientific decision basis for the virtual power plant to participate in grid control, such that it has a great value in an actual application.

Abstract: The present disclosure provides a scheduling method for a power system based on flexible HVDC (high-voltage direct current) and a pumped storage power station, which belongs to a field of power system control technologies. The method is applicable in a power system having a flexible HVDC system and a pumped storage power station. By establishing a scheduling model for the power system, which contains an objective function and multiple constraints, and solving the scheduling model, a capability of the pumped storage power station is used to adjust the unstable output of the renewable energy power generator and stabilize fluctuant of the renewable energy power generation, such that a power incoming into a load center presents a stable ladder pattern and an optimal scheduling scheme can be obtained.

Abstract: The present disclosure provides a method for optimizing transformation of automation equipment in a power distribution network based on reliability, including determining installation states of respective components in the power distribution network and operation criterions for fault isolation, load transfer and fault recovery after a fault occurred in a feeder segment; determining a target function which is a target function for minimizing a total transformation cost of the power distribution network; determining constraint conditions including reliability constraints; establishing an optimization model for evaluating the reliability of the power distribution network based on the reliability constraints in accordance with the target function and the constraints; and solving the established optimization model for evaluating the reliability of the power distribution network based on the reliability constraints to obtain optimal solutions as optimization results of the automation transformation state of the cir

Abstract: The disclosure provides a method for calculating a parameter changing domain of loads under a case that guarantees a constant locational marginal price in an electricity market, which relates to the electricity market field of the power system. With the method in the disclosure, the clearing model on the locational marginal price in the general form is established, and the safe changing domain of the locational marginal price with respect to the loads may be derived and calculated based on the first-order KKT condition expansion of the clearing model on the locational marginal price in the general form. The method may quickly calculate the parameter changing domain of different nodal loads under the condition of a clear base state in the current power market. When the increment of the nodal loads is subordinate to the changing domain, the locational marginal price may remain unchanged.