Abstract: The present invention relates to the technical field of fault location of distributed energy resources connected flexible DC distribution network, and disclosed a fault location method, system and application of bipolar short-circuit of two-level VSC-type photovoltaic-connected flexible DC distribution network, wherein, directions of positive currents of DC feeders during fault are used to locate a fault section; a bipolar short-circuit distance measurement model covering interactions and responses of systems is established according to equivalent circuits of transient periods; and fault location is done by obtaining a distance to fault with electric parameters and information of the fault.

Abstract: Disclosed is a construction method for a cantilever beam on a central pier. A scaled model of the cantilever beam on the central pier is established and tested to obtain the stress distribution regularities of the cantilever beam according to test data and analysis results of the scaled model, so as to find out week parts of the cantilever beam, and thus the optimization design can be performed to make the cantilever beam reasonably carry the load and improve the materials with a higher utilization ratio. The wheeled stand support used in the present application has a high turnover rate and it is easy and convenient to dismantle and assemble the wheeled stand support. A height of the cantilever beam mold can be adjusted by a hydraulic cylinder.

Abstract: A construction method for a cantilever beam on a central pier. A scaled model of the cantilever beam on the central pier is established and tested to obtain the stress distribution regularities of the cantilever beam according to test data and analysis results of the scaled model, so as to find out week parts of the cantilever beam, and thus the optimization design can be performed to make the cantilever beam reasonably carry the load and improve the materials with a higher utilization ratio. The wheeled stand support used in the present application has a high turnover rate and it is easy and convenient to dismantle and assemble the wheeled stand support. A height of the cantilever beam mold can be adjusted by a hydraulic cylinder.

Abstract: In an ultraviolet LED chip, an epitaxial structure can be isolated into two insulated structures, i.e. a first and a second epitaxial structures by growing the epitaxial structure on a surface of a substrate, and arranging an insulating layer and a groove contacting layer in the middle of the epitaxial structure. The N-type AlGaN layer is stretched out through the groove contacting layer. In the ultraviolet LED chip, through the cooperation among the N electrode, P electrode and intermediate electrode on the base plate along with the first and second epitaxial structures, an LED and an ESD are formed respectively. The ESD is connect to the ends of LED in anti-parallel for providing an electrostatic discharging channel, so as to reduce the direct damage of the ultraviolet LED chip caused by electrostatic discharging, and increase a forward voltage of the LED and the antistatic intensity.

Abstract: In an ultraviolet LED chip, an epitaxial structure can be isolated into two insulated structures, i.e. a first and a second epitaxial structures by growing the epitaxial structure on a surface of a substrate, and arranging an insulating layer and a groove contacting layer in the middle of the epitaxial structure. The N-type AlGaN layer is stretched out through the groove contacting layer. In the ultraviolet LED chip, through the cooperation among the N electrode, P electrode and intermediate electrode on the base plate along with the first and second epitaxial structures, an LED and an ESD are formed respectively. The ESD is connect to the ends of LED in anti-parallel for providing an electrostatic discharging channel, so as to reduce the direct damage of the ultraviolet LED chip caused by electrostatic discharging, and increase a forward voltage of the LED and the antistatic intensity.

Abstract: A method for optimizing the flexible constraints of an electric power system includes a step S1 of expressing the total power generation cost of the electric power system by using the sum of quadratic functions of active power outputs of all generator sets in the system and constructing an objective function, a step S2 of selecting a multi-dimensional flexible optimization model or a flexible power generation cost optimization model according to the practical situation of the electric power system and the practical purpose of optimization, a step S3 of determining the operating conditions of the electric power system, and a step S4 of carrying out load flow calculation.

Abstract: A method for optimizing the flexible constraints of an electric power system includes a step S1 of expressing the total power generation cost of the electric power system by using the sum of quadratic functions of active power outputs of all generator sets in the system and constructing an objective function, a step S2 of selecting a multi-dimensional flexible optimization model or a flexible power generation cost optimization model according to the practical situation of the electric power system and the practical purpose of optimization, a step S3 of determining the operating conditions of the electric power system, and a step S4 of carrying out load flow calculation.