electrical network

Distribution networks with a voltage of 35 kV are mostly used to supply electricity consumers located in rural areas. These networks, which mainly have overhead lines, normally function according to the radial principle, although in most cases they are closed or with two-way power. In recent years, the structure of 35 kV electric network has been changing, they are being transformed from aerial to aerial- cable due to the construction of 35 kV cable lines in rural areas, which in most cases are performed with cables with cross-linked polyethylene insulation.

One of the current issues in a complex electrical network with isolated (compensated) neutral is the selective identification of the damaged element during a single-phase-to-ground fault (SPGF). In order to achieve selective and reliable operation of protections against SPGFs in complex networks with isolated (compensated) neutral, besides information about the zero-sequence current and connection, information about phase voltages, zero-sequence voltage of the electrical network, and the operation of protection devices against adjacent SPGFs is necessary.

One of the problems in the electrical network with isolated (compensated) neutral is the selective determination of the damaged element in a single-phase earth fault. For selective and reliable operation of protections against single-phase earth faults in networks with isolated (compensated) neutral, in addition to the zero-sequence current, information on phase voltages and zero-sequence voltage of the electrical network is required. Many transformer substations do not have traditional electromagnetic voltage transformers.

On the basis of a generalized interdisciplinary (interdisciplinary) method of mathema- tical modeling, which is based on modifications of the integral variational principle of Ha- milton-Ostrogradsky, proposed mathematical model of the ultra-high voltage circuit-breaker the main emphasis of which is placed on modeling work the mechanism of moving his contacts.

On the basis of computer simulation researched the influence of the grounding conditions of neutral of electrical network 35 kV on the level of arc, commutation, ferorezonansni overvoltage. Shown that the values of arc overvoltage and character development ferorezonans processes is significantly affected mode neutral grounding network. There were given schematic dependencies of arc overvoltage multiplicities which depend on the nature of combustion of grounding arc, grid configuration and the conditions of neutral grounding.

It has been offered the algorithms determine the optimal location of distribution substations or switchgear for the electrical system , taking into account external power line. Optimality criterion selected discounted costs. It is shown that the optimal position location distribution substation (switching substation) is shifted from the centre of electrical loads in the direction of power.

The additive model with separation of a basic regular component and an random component for short-term forecasting of loading an power plant is offered