SU1206881A1 - Filtering-symmetrizing device for three-phase networks with zero phase wire - Google Patents

Description

The invention relates to electrical engineering and can be used to improve the quality of electrical energy and to compensate for: reactive power in three-phase networks with a neutral wire (for example, in urban and rural distribution networks) containing asymmetrical (single-phase) and non-linear loads, varying in size and phase, as well as on the electrical power inputs of electronic equipment (computers, ABMs, ACS, etc.), which cannot function highly productively at low quality of the supplied electric power, especially when carrying metric phase voltages and the flow of currents of higher harmonics.

The aim of the invention is to improve the quality of the voltage.

FIG. Figure 1 shows the current pialy diagram of the filter-symmetrizing device (FSC); in fig. 2 is a diagram of the inclusion of the FSU in the network, on

FIG. 3 and FIG. 4 - amplitude-frequency-25 apparatus, the windings of which are connected characteristics, respectively, of the known and proposed FSU.

The device (Fig. 1) contains phase A, B, and C and is zero. About the mains wire, phase A, B and C, and neutralization of the terminals of the FSU, windings 1-6 of the FSU, connected according to the opposite zigzag circuit, capacitor banks 7 -9 FSU,

.ny on scheme zatrazny zigzag. This is due to the fact that this device has an extremely low zero-sequence resistance, 30 T.e. The shogi are zero-sequence currents created by the network with a network load, closed through this device.

The device (Fig. 2) contains a FSU 10, an equivalent asym-1metric and non-linear load of the 11 (N) network, an electronic (computer, etc.) equipment 12 protected by the FSU from high harmonic currents and phase voltage unbalance.

The FSU contains a 1-t electromagnetic apparatus, the windings 1-6 of which are connected according to the counter-zigzag scheme, and three capacitor batteries 7-9. Conclusions capacitor banks. 7-9 are connected respectively between the phase A, B and C, and the neutral-to-1 O terminals of the FSA, the result is that each capacitor battery is connected to a parallel direct two, sequentially oppositely connected to the windings of the FSU. For example, a capacitor battery 7 is connected between the lead A and O, and thus the windings 4 and 2 are connected in parallel. In the proposed FSF, the inductances of all six windings 1-6 are equal to each other and the capacitance values

All three capacitor batteries 7-9 are also equal.

The proposed FSU allows filtering high harmonic currents of the forward, reverse, and zero sequences, as well as balancing the voltages in the phases of the network with zero wire. In other words, the FSU is designed to improve the quality of the voltage at the terminals of the responsible consumers and to eliminate the flow of higher harmonics in the network section where such consumers are connected. As can be seen from the scheme of the inclusion of the FSU 10 in the network, the asymmetry and nonlinearity currents created by asymmetric and nonlinear loads 11 , are closed at FSZ 10 and do not flow through electronic equipment circuits 12.

The metering of the phase voltages of the network is ensured by the presence in the FSU of a three-phase electromagnetic

25 apparatus, the windings of which

.ny on scheme zatrazny zigzag. This is due to the fact that this device has an extremely low zero-sequence resistance, 30 T.e. The shogi are zero-sequence currents created by the network with a network load, closed through this device.

Resistance 2 neck 6 0.03 ohms, and direct and reverse sequences

  fsu 600 ohm. : ..

Since this device has a very low resistance of the zero sequence, which is equivalent to a small resistance for harmonic currents of a multiple of three, when the non-linear and conventional asymmetrical loads are connected together to the FSU network, all the higher harmonics currents have 6 times Txi i, and also. high-order zero-sequence currents are closed through the device „

 The amplitude-frequency characteristic of the device is shown in Fig. 4, from which it can be seen that the resistances of the direct, inverse, and zero sequences of the device increase with S) changing from 1 to -i, (i 1, 2) and decreasing to O with changing t) from -J; before oo In other words, depending on the parameters of the device and the network, broadband is possible.

FILTRANA D1 of high harmonic currents at the place of switching on the FSU.

The capacitors of the capacitors of the FSA batteries are determined depending on the parameters of the network replacement circuit. So, for a given filtered. harmonics esse. which is chosen depending on the amplitude source of nonlinear distortion, we will have:

E6M

12

1u1CHP1 / 7 „7

"" "E-)

Where

X (. Is the resistance value of conJ -ll /.-.- - - - - f.

FSU sensor battery at the main frequency for broadband filtering of higher harmonics, starting with

P X - equivalent resistances of the network replacement circuit at the fundamental frequency.

5 С

FSU

ten

AND

ff

./z;/ / z ;; /

ed- / 2; / y

/ 4 / y "/ 2 // y

Fig.Ch

Editor R. Tsitsika

Compiled by I. Miroshnikov

Tehred L. Mikesh Proofreader L. Pilipenko. |

Order 8728/55 Circulation 3 Subscription

VNIIGSh of the USSR State Committee

for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5

PLI Patent Branch, Uzhgorod, Proektna St., 4

Claims (1)

A FILTROSYMMETRING DEVICE FOR THREE-PHASE NETWORKS WITH A ZERO WIRE, containing a three-phase electromagnetic device, the windings of which are connected in an oncoming zigzag circuit, which has three phases (one terminals and one neutral, with each phase terminal being connected to the phase wires of the network, and the neutral one to zero , characterized in that, in order to improve the quality of the voltage, it is equipped with / three capacitor banks, the terminals of each of which are connected respectively between the phase and neutral terminals of the ele magnetic apparatus. Figure 1