SU1220054A1 - Combined three-phase filter equalizing device - Google Patents

Description

The invention relates to electrical engineering and is intended to improve the quality of electrical energy 9 power supply systems of nonlinear loads.

The aim of the invention is to increase the reliability of the device and expand its functionality.

FIG. 1 is a schematic diagram of the proposed device, the phases of the device interconnected by a star; in fig. 2 - the same, phases of the device connected among themselves by a triangle.

The device consists of three arms (phases) 1-3. In this case, the capacitor 4, the reactor 5, the condenser 6 and the reactor 7 are interconnected sequentially and connected between two phase clamps of the supply network. The capacitor 8 in the switching phase of the device is connected between the common point of the condenser 4 and the reactor 5 and the common point of the capacitor 6 and the reactor 7. At this point, points of the reactor 5 and the capacitors .6 are either connected to the common point of the device (Fig. 1) or connected to the corresponding phase terminals of the power supply network (Fig. 2). For greater consistency, the invention can be regarded as containing in each phase three capacitors 4, 8 6 connected in series with each other, connected between two phase terminals of the network (Fig. 2) or between a phase terminal of the network and a common point of the device (Fig. 1 ). The device contains in each phase two reactors 5 and 7, which are connected to the common point of the first 4 and second 8 capacitors (reactor 5) and the common point of the second 8 and third 6 capacitors (reactor 7) with their first devices. Secondly, reactor 5 is connected to the free output of the third capacitor 6, and reactor 7 to the corresponding phase terminal of the power supply network (to that phase power supply terminal to which the free terminals of the first 4 or third 7 capacitors of this arm 1, 2 or 3 are not connected devices).

The device is static, i. E. its mode of operation is determined by the specific connection scheme between itself and with the phase clamps of the network of its capacitor-reactor elements 4-8. Dp of low frequency harmonics (for example, for the mains frequency) the resistances of reactors 5 and 7 are insignificant. In this case, the capacitors 4, 8, and 6 are conventionally connected to each other in parallel, and a phase (Fig. 1) or linear (Fig. 2) network voltage is applied to each of them. In this case, the maximum possible amount of reactive power generated in the network is provided. For higher harmonics of the sound spectrum, on the contrary, the resistances of reactors 5 and 7 are too large and their conductivities can be neglected. In this case, the higher harmonics and overvoltages from the network side are closed through the capacitors 4, 2 and 6 of each device connected in series with each other. Action of these

higher harmonics and overvoltages for each of the capacitors 2, 4, 6 are individually reduced by a factor of three, which ensures that the reliability of the filter-compensating device is reliable. It is known that the passage of current through series-connected capacitors and reactors causes resonance at certain harmonics, in which the resistance

the corresponding branch is zero, the currents of these harmonics are shunted. In the proposed device, containing two reactors 5-7 in each arm (phase 1-3), resonance is provided

three harmonics. Indeed, the current from one external point of each arm 1-3 to the other and third external points passes through three branches containing capacitor-reactor

branches: a) through the capacitor 4 and the reactor 5; b) through capacitors 4 and 8 and reactor 7; c) through capacitors 4 and reactors 5 and 7. 1.

So with the appropriate

selecting the parameters of capacitors 4, 6, 8 and reactors 5, 7, the device provides shunting (filtering) of three specific harmonics and all higher harmonics of sound

spectrum.

Claims (1)

Invention Formula The combined three-phase filter-compensating device, which in each phase contains three capacitors connected in series, is free from the first 31 of which are connected to one of the three-phase power supply terminals, and the free output of the third of which is connected to the second phase terminal of the network or the common point of all phases, two reactors, the first of which is connected to the common points of the first and second capacitors by its first output, and the second with its first pin to the common points of the second and third capacitors, 2005 and 20054 Of course, in order to increase the reliability of the device and expand its functionality, the second end of the first reactor in each phase is connected to the free output of the third capacitor, the output of the second reactor is connected to the phase terminal of the power supply network, you are not connected to the free ryo - 10 water of the first or third capacitor of this phase of the device.