55results about How to "Improve voltage distribution" patented technology

The invention relates to a VSC-converter for converting direct voltage into auxiliary voltage and vice versa, which comprises a series connection of at least two current valves (5, 6) arranged between two poles (7, 8), a positive and a negative, of a direct voltage side of the converter, each current valve comprising several series connected circuits (12), each of which circuits comprising a semiconductor component (13) of turn-off type and a rectifying component (14) connected in anti-parallel therewith, an alternating voltage phase line (16) being connected to a midpoint (15), denominated phase output, of the series connection of current valves (5, 6) between two of said current valves while dividing the series connection into two equal parts. Each of the series connected circuits (12) of the respective current valve comprises, in order to make possible a good voltage distribution between the semiconductor components (13) of turn-off type included in the respective current valve, a snubber capacitor (17) connected in parallel with the semiconductor component (13) of turn-off type included in the circuit. The converter (1) further comprises a resonance circuit (18) for recharging the snubber capacitors (17) of the current valves.

The invention relates to a large photovoltaic power station reactive optimization method based on improved immune particle swarm optimization algorithm, and belongs to the technical field of photovoltaic power station control. The method comprises the following steps: 1) establishing a photovoltaic power station stable state operation model to analyzing the voltage, wherein the model comprises an instation current collection line, a step up transformer and power transmission line impedance; 2) establishing a multi-target reactive power optimization model, and performing fuzzy processing of multiple targets; and 3) solving by using the improved immune particle swarm optimization algorithm. The large photovoltaic power station reactive optimization method based on improved immune particle swarm optimization algorithm can significantly improve the grid-connection point voltage and the instation voltage distribution, and can significantly reduce the instation active loss when the power station outputs greatly.

The invention discloses an optimized load shedding method with consideration of the influence of a distributed power supply. All nodes in a distribution network upload interruptible load capacities ata current time and load priority levels to a centralized controller at a root node and the centralized controller establishes an optimized load shedding model with consideration of an outer net equivalence according to the uploaded information and a flow restraint; the centralized controller converts a non-linear flow restraint into one in a convex second-order cone mode by means of second-ordercone relaxation and thus calculates an optimized load shedding value with consideration of the distributed power supply output influence rapidly, and issues the information to all node control units;after all nodes perform a load shedding action, a measuring unit monitors whether the node voltages are restored to be in a rated range and determines whether to complete the load shedding process. With the method disclosed by the invention, quick and precise load shedding controlling is realized in a distribution network including lots of distributed power supplies and the voltage of the distribution network is restored to the greatest extent; limit exceeding of the voltage of the distributed power supply is avoided; and thus over-voltage tripping of the distributed power supply caused by theimproper load shedding is avoided.

The invention relates to a terminal connection box for an optical phase conductor, which is an optical cable connection box for 220KV optical phase conductor (OPPC). The connection box is provided with an upper box body and a lower box body, a composite hollow insulator is arranged between the upper box body and the lower box body, and an equalizing ring is arranged between the upper box body and the composite hollow insulator; the upper box body is provided with an optical phase conductor clamp, and a cable feeding hole is provided with an introduction tube, a rubber ring I and a nut; the cable feeding hole is internally provided with a rubber cone I and a small pressure ring I; the bottom of the upper box body is provided with a large pressure ring, a small pressure ring II and a rubber cone II; the large pressure ring is provided with a support screw I, a disc fiber board I and a disc fiber board cover I; the upper part of the upper box body is provided with a sealing gasket and an upper cover; the composite hollow insulator is internally penetrated by an optical fiber unit and filled with silica gel; the lower box body is provided with a sealing device of the optical fiber unit, an introduction cable of the lower box body is provided with an introduction cable clamp, a rubber ring II and a nut II; and the lower box body is internally provided with an optical fiber storage device.

The invention discloses a reactive power optimization control method based on active power output of a photovoltaic power station, belonging to the technical field of photovoltaic power station operation control. The method of the invention comprises: the parameters of each photovoltaic inverter and SVG in the photovoltaic power station are obtained, The active power output P* of the photovoltaicpower station and the voltage control instruction of the grid connection point issued by the grid dispatching center (img file = 'DDA000179000293000011. TIF' wi= '126' he= '86'/) are calculated to obtain the reactive power compensation amount of the photovoltaic power station Q*; Calculate the reactive power capacity Qmax, Qmin of the photovoltaic power station; Taking the reactive power output ofPVGU and SVG as the control object, taking the minimum voltage deviation and the minimum active power loss of photovoltaic power station as the optimization objective, and transforming the fuzzy theory into a single objective optimization problem, the reactive power optimization control model based on the active power output of photovoltaic power station is established. Differential evolutionaryalgorithm is used to solve the model.

The invention relates to a high-voltage AC (alternate current) and DC (direct current) voltage divider with a heat dissipation structure and belongs to the field of calibration, verification and detection of power equipment. According to the invention, radiating fins are arranged on the lower surface of a cover board and the outer surface of a conductive outer barrel of the high-voltage AC and DC voltage divider, a closed cavity is surrounded by a chassis, the cover board, the conductive outer barrel and an insulating outer barrel and insulating gas or oil is filled into the cavity, so that the effect of rapidly transferring heat inside the voltage divider into the outside environment is achieved, the temperature gradient of inner and outer barrels is effectively reduced, the potentials inside and outside the voltage divider are kept consistent and the measurement accuracy and the using safety are improved.

The invention provides a dynamic voltage regulation control method under a distributed photovoltaic-cluster non-communication condition and belongs to the electric power system operation and control technology field. The method comprises the following steps of establishing a distributed photovoltaic cluster voltage optimization model and a branch trend equation of a distributed photovoltaic cluster respectively, and carrying out linearization on the branch trend equation so as to obtain the branch trend equation of distributed photovoltaic cluster linearization, and converting to a matrix branch trend equation; after solving a matrix equation, converting the optimization model so as to acquire an approximate optimization model; using a distributed quasi-Newton method to solve the approximate optimization model; based on an iterative result, carrying out reactive power control on each node in the distributed photovoltaic cluster and determining whether iteration converges; and if the iteration converges, ending voltage control of the distributed photovoltaic cluster. By using the method, a reactive power regulation capability of distributed photovoltaic power generating nodes is fully used, construction of a communication system is avoided, a calculating burden of the system is mitigated and operation and maintenance cost is reduced.

The invention provides a voltage bilevel optimization droop control method for a distributed photovoltaic cluster, which belongs to the technical field of power system operation and control. The method includes steps of: establishing a distributed photovoltaic cluster droop curve optimization layer and a distributed photovoltaic local reactive power control layer respectively, two levels executingsimultaneously and separately, and the distributed photovoltaic cluster droop curve optimization layer periodically sending the optimization result to the distributed photovoltaic local reactive power control layer to enable the latter to adjust the reactive power output in real time according to the fluctuation of the system state, respond to the system's reactive power regulation requirements to the greatest extent, solve the contradiction between optimization calculation, cycle communication and real-time control, and reduce the photovoltaic off-net risk. The method fully utilizes the reactive power adjustment capability of distributed photovoltaic power generation nodes, reduces the calculation burden of the system, and reduces the operation and maintenance cost.

The present application relates to a micro-grid energy storage optimal configuration method and device in consideration of full life cycle cost. The micro-grid energy storage optimal configuration method in consideration of full life cycle cost includes: obtaining the data of an energy storage system to be configured to obtain target data; obtaining a pre-established energy storage optimization model, the energy storage optimization model including an outer layer optimization model and an inner layer optimization model; based on the target data, obtaining the optimal solution of the energy storage optimization model by a genetic algorithm and a simulated annealing algorithm so as to obtain an optimal configuration result, wherein the optimal configuration result at least includes the ratedpower, the rated capacity and the economic operating power; and configuring the energy storage system to be configured according to the optimal configuration result. The method provided by the present application can minimize the cost and maximize the benefits of the energy storage system during the full life cycle.

The invention provides a normalized load moment and distributed power supply access power distribution network-based low-voltage treatment method. The method comprises the steps of S1, calculating to obtain the load moment of each line meeting the minimum voltage; s2, selecting a to-be-accessed position of the distributed power supply based on the load moment; s3, constructing an objective function of a locating and sizing model for accessing the distributed power supply to the power distribution network; and S4, determining constraint conditions of the distributed power supply access power distribution network locating and sizing model, and finally determining the access address and capacity of the distributed power supply. According to the method, the problem that the load moment cannot be solved when lines of different models are connected in a mixed mode is solved, voltage distribution is improved through locating and sizing of the distributed power supply based on the normalized load moment, meanwhile, the investment cost of a power distribution network can be reduced, and economic benefits are improved.

The invention relates to a mixed integer linear programming model for the optimal operation of a power distribution network energy storage system. Because the number of the battery energy storage systems deployed in a power distribution system is continuously increased, a new model is needed to describe the real characteristics. Besides the active power, the energy storage system can also exchangethe active power with the power grid through inverter connection. Although some existing work considers the problem, research on a linear model suitable for an actual large-scale power distribution system is not sufficient enough. Under the background, the mixed integer linear programming model for the optimized operation of the power distribution network energy storage system is provided. First,the model considers various parts of a battery energy storage system, including a battery pack, an inverter and a transformer, and the linear modeling of active power and apparent power limits, and then, the system power loss is calculated by adopting a linear power flow model, so that the precision is higher.

Provided is a suspension insulator capable of individual improvement of damaged voltage resistance and damaged corona discharge prevention. With the suspension insulator equipped with a plurality of ring- shaped ribs formed with a pin metal fitting implanted at the center part as an axis on the undersurface just outside where glaze is applied, a resistance strip 31 with a surface resistance (1 cm× 1 cm) of not more than 4 MΩ is set, a ring-shaped conductive strip 32 at an outer periphery of the resistance strip 31, and further, (1) a conductive glaze layer consisting of the resistance strip 31 and the conductive strip 32 is fitted inside the ribs having a length of not less than 4% of leakage distance, and/or, (2) diameter of the outer periphery of the conductive glaze layer of the underside consisting of the resistance strip 31 and the conductive strip 32 is to be not more than twice that of a cap part on the top face.

The spark clearance has as much possible partial spark clearances connected in series, in particular, these partial spark clearances are wired by capacitor (6) except the first spark clearance reacting in the case of overvoltage phenomenon, and, in particular, the second spark clearance and each spark clearance other than it are connected with common reference electric potential (4), particularly, ground potential through the capacity (6). To markedly improve reaction characteristic of a spark clearance, a bypass (7) composed of an auxiliary spark clearance (8) having a smaller reaction voltage than a reaction voltage of a single spark clearance or these partial spark clearances and at least one varistor (9) is connected in parallel with a multiple spark clearance composed of the single spark clearance or a plurality of partial spark clearances connected in series.

A barrier-film forming apparatus that forms a barrier film on an inner face of a container having a concave or convex portion as a processing target, including: a dielectric member having a cavity sized to enclose the container, an external electrode covering an outer circumference of the dielectric member, an exhaust unit installed on an end face of the external electrode on a side where a mouth of the container is located, with an insulating member interposed therebetween, and depressurizing inside of the container through an exhaust pipe, an internal electrode inserted from a side of the exhaust pipe and also serving as a gas blowout unit that blows out medium gas for generating a barrier film into the container, and an electric-field applying unit that applies an electric field for generating exhaust between the external electrode and a ground electrode.

Electrical switchgear, e.g. a circuit breaker, must in general provide good dielectric strength in open position in order to avoid discharge. To improve the dielectric strength capacitors are often arranged in parallel between the contacts of the switchgear. For very high voltage applications, e.g. >500kV, two circuit breaker are connected in series for switching such high voltages, i.e. the total voltage to be switched needs to be shared equally by the two switches. Because of the required capacitance the capacitor and hence also the switchgear is big, especially of great diameter, and costly. According to the present invention shields (10, 11) are arranged in order to form additional capacitors C1'', C1''' and C₂ between the shields (10, 11) and between a connecting means (4), connecting the two switches (2, 3), and the enclosure (5). The resulting switchgear 1 has increased dielectric strength and the total voltage is essentially equally shared by the two switches (2, 3) in series.

The invention discloses a longitudinally and transversely arranged gridding alternating current and direct current hybrid power distribution network, which comprises a transversely arranged AC line and a longitudinally arranged DC line, a transverter is arranged at a cross point needing AC/DC power exchange, the AC line is connected with a power transmission network power supply and an AC load, and the DC line is connected with a distributed power generation power supply and a DC load. The AC line and the DC line are both provided with a plurality of circuit breakers, and the connection branch between each converter and the AC line and the connection branch between each converter and the DC line are also provided with circuit breakers. Voltage distribution and load bearing capacity of an original alternating-current line are effectively improved, power supply quality is improved, power supply corridor configuration is flexible, and the problem of shortage of power supply corridors during capacity increasing of a current power distribution network is effectively relieved; a conversion link required during grid-connected operation of the load, the distributed power supply and the energy storage equipment is simplified, the utilization rate is increased, and the overall energy efficiency of the system is improved; the power supply reliability is very high; and the expandability is good.