RU132636U1 - DAMPED NETWORK FILTER - Google Patents

Abstract

1. A damped line filter containing a main capacitor, an additional capacitor and an inductor connected in series to form the first resonant link, the additional capacitor and inductor tuned to a voltage resonance at a frequency of 50 Hz, and a damping resistor connected in parallel with the first resonant link with this condition in order to damp the entire resonant link tuned to the voltage resonance at the selected harmonic, characterized in that it is parallel an inductor connected RC-circuit of a second resistor and a third capacitor, the magnitude of the third capacitance Svybiraetsya an order of magnitude smaller than the main capacitor and the second resistor resistance value is selected by an order of magnitude smaller than the main rezistora.2 resistance. The damped line filter according to claim 1, characterized in that the resistance value of the second resistor can be selected equal to zero.

Description

The utility model relates to the field of electrical engineering, in particular to devices that can reduce impulse noise in a single-phase or three-phase electrical network.

Known damped line filters (SSF), designed to suppress one higher harmonic current non-sinusoidal load in a single-phase or three-phase network [1, 2].

Closest to the claimed utility model is a circuit solution known from [1] (FIG. 1), which contains a main capacitor C ₁ , a series capacitor C ₂ and an inductor L connected in series, with C ₂ and L tuned to a voltage resonance at a frequency 50 Hz (frequency of an industrial electric network). The damping resistor R _{1 is} connected in parallel with the resonant link C ₂ L so that it does not dissipate the electric power at the mains frequency, but damps the entire resonant link C ₁ C ₂ L tuned to the voltage resonance at the selected harmonic (for example, the third, as the most important for an industrial network with a 0.4 kV neutral).

The disadvantages of the prototype:

impulse noise in the network is suppressed weakly, inefficiently, due to the relatively large value of the resistor R resistance;

the difficulty of tuning the resonance at a frequency of 50 Hz.

The technical result achieved by the claimed utility model is to improve the quality of power supply, reduce power losses in electric networks by suppressing impulse noise in the network, and also simplify resonance tuning at a frequency of 50 Hz.

The technical result is achieved by the fact that in a damped line filter containing the main capacitor, an additional capacitor and an inductor are connected in series, forming the first resonant link, the additional capacitor and inductor configured for voltage resonance at a frequency of 50 Hz, and a damping resistor connected in parallel with the first resonant link with such a condition as to damp the entire resonant link tuned to the voltage resonance at the selected according to the utility model, an RC circuit from a second resistor and a third capacitor is connected parallel to the inductor, moreover, the capacitance of the third capacitor is selected by an order of magnitude less than the value of the main capacitor, and the resistance value of the second resistor is selected by an order of magnitude less than the resistance of the main resistor.

In this case, the resistance value of the second resistor can be chosen equal to zero.

The inventive utility model is illustrated by the following graphic materials.

Figure 1 is a diagram of the closest analogue.

Figure 2 - diagram of the inventive damped line filter.

The inventive damped line filter (figure 2) contains the main capacitor 1, sequentially connected an additional capacitor 2 and an inductor 3 forming a full resonant link 1, 2, 3, and a damping resistor 4.

Serially connected additional capacitor 2 and inductor 3 form the first resonant link 2, 3.

The damping resistor 4 is connected in parallel with the first resonant link 2, 3. In parallel with the inductor 3, an RC circuit from the second resistor 5 and the third capacitor 6 is connected.

Additional capacitor 2 and inductor 3 are tuned for voltage resonance at a frequency of 50 Hz. The damping resistor 4 is connected in parallel with the first resonant link 2, 3 so that it damps the entire resonant link 1, 2, 3 tuned to the voltage resonance at the selected harmonic.

The capacitance value of the third capacitor 6 is selected by an order of magnitude less than the value of the main capacitor 1, and the resistance value of the second resistor 5 is selected by an order of magnitude less than the resistance value of the main resistor 4.

The resistance value of the second resistor 5 can be selected equal to zero.

The inventive damped surge protector operates as follows.

When you turn on the device in the network at the first moment, according to the switching law for electric capacitors (the voltage on the capacitor cannot change abruptly), the voltage on all capacitors is zero, therefore the network at this moment is loaded mainly on the second resistor 5. There is a current surge, in magnitude which should select the parameters of the second resistor 5 and its protective device. Similarly, when a sharp voltage pulse occurs in the network, it will be suppressed in the second resistor 5, since the value of its resistance is much less than the values of the inductive resistances of the network elements at high frequencies corresponding to a short pulse.

As a result, the impulse noise will be suppressed more strongly, more efficiently than in the prototype, since at high frequencies the equivalent active resistance of the inventive damped line filter will be determined only by resistor 5. By changing within a small range (± 20%) the capacitance of the capacitor 6, a relatively small capacity compared with capacitor 2, it is easier to achieve voltage resonance at a frequency of 50 Hz in the first resonant link 2, 3.

Example 1

R ₁ = 50 Ohms, R ₂ ≈5 Ohms

If C ₁ ≈1800 μF, U = 450 V, then C ₃ ≈100 μF, U = 100 V

Example 2

C ₁ ≈1000 μF, at 16.6 kvar

C ₂ ≈ 9000 microfarads (third harmonic)

R ₁ ≈20 Ohm

C ₃ ≈100 μF, R ₂ ≈2 Ohm

Thus, in the claimed utility model

- a reduction is achieved up to a possible minimum loss of active energy at a frequency of 50 Hz in the main damping resistor R ₁ ;

- finely tuned to a frequency of 50 Hz circuit LC ₂ ;

- there is an effective suppression of impulse noise in the network.

INFORMATION SOURCES.

1. Borodullin B.M., German L.A., Nikolaev G.A. Condenser installations of electrified railways. - M .: Transport. 1983, p. 66.

2. Zhezhelenko I.V. Higher harmonics in power supply systems of industrial enterprises. - M .: Energoatomizdat. 1994, p. 272.

Claims (2)

1. A damped line filter containing a main capacitor, an additional capacitor and an inductor connected in series to form the first resonant link, the additional capacitor and inductor tuned to a voltage resonance at a frequency of 50 Hz, and a damping resistor connected in parallel with the first resonant link with this condition in order to damp the entire resonant link tuned to the voltage resonance at the selected harmonic, characterized in that it is parallel an inductor connected RC-circuit of a second resistor and a third capacitor, the magnitude of the third capacitance C ₃ is selected in the order of magnitude smaller than the main capacitor and the second resistor resistance value is selected by an order of magnitude smaller than the main resistor. 2. The damped line filter according to claim 1, characterized in that the resistance value of the second resistor can be selected equal to zero.

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