39results about How to "Avoid cascading failures" patented technology

The invention relates to a method for simulating a power grid interlocking fault based on complicated network theoretical calculation and correction control, and belongs to the technical field of safety and reliability protection of power systems. The method comprises the following steps of utilizing a computer, and performing procedures; firstly, calculating the optimum trend of a power system under the normal condition; calculating the betweenness of each node, determining a betweenness threshold value of each node of the power system, simulating the interlocking fault of the power system, and finally calculating the total loss load of the interlocking fault. The method has the advantages that under the condition of meeting the safety running constraint requirement of the power system, the influence of correction control on the interlocking fault can be simulated by adjusting the output power and reduced load of a power generator, the influence of the change of load distribution on the interlocking fault can be reflected, and the propagation process of the interlocking fault of the power system can be well reflected; the method is widely applied to simulate the interlocking fault of the power system, is particularly suitable for simulating the interlocking fault of large complicated power systems, and can provide scientific basis for preventing the occurrence of the interlocking fault of the power system.

The invention relates to a cascading failure search and weak link analysis method based on an operation reliability model. The method comprises steps: initial failure is generated randomly; a DC power flow is calculated, whether a load threshold-crossing line exists in a power system is judged, if yes, a next step is carried out, or otherwise, the operation is stopped; an initial failure set is generated, and through the operation reliability model, the threshold-crossing line outage probability is calculated; the power system state probability is calculated; if the power state probability is larger than a set threshold and the failure scale is smaller than a set threshold, the power state is added to an alternative failure set, and if no state meeting the condition exists, search is stopped; the initial failure set is taken as an alternative failure set, the current alternative failure set is emptied, and the above steps are repeated. Through searching a cascading failure event in different initial failure and analyzing a system weak link, a corresponding system reform scheme is provided, happening of the cascading failure is prevented, a subsequent event is found during an event development process, and further evolution of the cascading event can be prevented.

The present invention proposes a composite dynamic power support system and method thereof, including a controller (1), an energy storage system, a controller (5), an energy storage controller (6) and comprehensive power dispatch management The system (7), wherein the AC outlet of the energy storage system is connected to the AC outlet of the condenser (1) and then connected to the AC power grid at the receiving end of the UHVDC transmission system; the power integrated regulation and control management system (7) is connected to the power grid dispatching system , to accept dispatching instructions from the grid dispatching system. The system adopts the combination of local control and centralized control, and integrates the reactive power support capability of the condenser (1) with the fast active power response capability of the energy storage system. Provide active and reactive power support for the AC power grid at the receiving end, and improve the safe and stable operation capability of the traditional AC power grid after being connected to the UHV DC transmission system.

The invention discloses a control method of a reactive power compensation device for preventing large-scale wind turbines from being disconnected from the grid, and belongs to the technical field of wind power generation. The invention sets the limit value of the low-voltage operation of the reactive power compensation device. When the voltage of the grid-connected point is lower than the value, it is judged that the grid is faulty, and the grid-connected switch will be automatically disconnected; after the fault is removed, the system control center will operate according to the network The state issues input commands to some reactive power compensation devices to ensure that the voltage quickly returns to the standard value. The invention can effectively avoid expansion of wind power system faults and prevent cascading faults.

The invention discloses a leader-follower game alternating current and direct current hybrid electric power system active defense strategy making method. The leader-follower game alternating current and direct current hybrid electric power system active defense strategy making method specifically comprises the following steps of (1) describing a leader-follower game process between an electric power system relevant department and a system fault through a defender-attacker-defender three-layer model; (2) establishing a leader-follower game model for making an active defense strategy of the alternating current and direct current hybrid electric power system; (3) solving the D-A-D (Defender-Attacker-Defender) three-layer model; (4) enabling an optimal active defense strategy obtained from the step (3) of the electric power system to perform active defense on the alternating current and direct current hybrid electric power system. The leader-follower game alternating current and direct current hybrid electric power system active defense strategy making method of the invention accurately determines a current fragile source for the electric power system under the condition that fault cannot be foreseen, adopts the corresponding active defense strategy and accordingly prevents generation of cascading failure.

The invention relates to a current sensorless grid-connected current control method suitable for a grid-connected inverter, and relates to a system composed of a main circuit of a grid-connected inverter and a control circuit of a grid-connected inverter. The circuit includes a grid current open-loop control module and a PWM generation module, the grid current open-loop control module includes a first proportional regulator, a second proportional regulator, a delayer and an adder, the first proportional regulator and the second proportional regulator The input terminals of the regulators are all taken out as the input terminals of the input current reference signal, the output terminal of the first proportional regulator is connected to the input terminal of the adder, the output terminal of the second proportional regulator is connected to the input terminal of the delayer, and the delayer The output end of the adder is connected to the input end of the adder, and the output end of the adder is connected to the PWM generating module. The open-loop current control method adopted by this system can realize the grid-incoming AC current without static difference to track the grid-incoming current reference signal, and can adapt to harsh operating scenarios such as grid harmonics, unbalance, and faults.