CN204441891U - A kind of resonance being series at distribution network feeder eliminates spacer assembly - Google Patents

Abstract

The utility model discloses a resonance elimination isolation device connected in series with a distribution network feeder, which comprises a main inductance coil (1), which is connected in parallel with a tuning element (T) and a protection element (2). 1. The isolation and elimination device for resonance between the distribution network and the electrical equipment is connected in series on the power supply feeder between the distribution network and the user; 2. Through the tuning of the main inductance coil (1) and the tuning element (T), the resonance Impedance is generated in the frequency band, and the parameter matching conditions for eliminating resonance are used to eliminate the resonance between the distribution network and electrical equipment; it solves the difficulties in the analysis, identification, and implementation of the existing resonance elimination measures, as well as the failure with the change of the grid operation mode It has the characteristics of simple measures, convenient implementation and strong adaptability.

Description

A resonance elimination isolation device connected in series with distribution network feeder

technical field

The utility model belongs to the field of power grid resonance overvoltage, relates to the prevention and control technology of distribution network resonance overvoltage caused by nonlinear load equipment, in particular to a resonance elimination isolation device connected in series with a distribution network feeder.

Background technique

Resonance is a phenomenon in the electromagnetic transient process of power system. There are many inductive and capacitive elements in the power system. When the system performs switching operations or fails, these capacitive and inductive elements may produce resonant parameter coordination to form an oscillation loop. When the system has non-linear loads (such as electromagnetic voltage transformers, electric arc furnaces), when the arc furnace starts and extinguishes arcs, or is subject to some large impact disturbances such as non-synchronous closing, or after the ground fault disappears, Or the closing inrush current of capacitive and inductive equipment will generate temporary resonant overvoltage in the circuit forming the coordination of resonance parameters, which poses a threat to the safety of power supply and electrical equipment.

This temporary resonant overvoltage may also saturate the non-linear inductor core coil, distort the waveform of the exciting current, convert the power frequency current energy into harmonic energy, and the resulting harmonic will become the harmonic that causes resonance. The harmonic source excites the resonant circuit to form a steady-state resonant overvoltage, that is, the ferromagnetic resonance overvoltage. The overvoltage and overcurrent when ferromagnetic resonance occurs will cause insulation flashover and blackout accidents; in severe cases, even equipment burnout and arrester explosion accidents will occur, threatening the safe operation of the power grid. Therefore, the study of resonance and its protective measures play an important role in preventing equipment insulation damage accidents and ensuring the safe operation of the power grid.

In particular, electrical equipment with nonlinear loads is likely to excite distribution network resonance. Nonlinear users such as electric arc furnace loads and electric locomotive loads release a large number of harmonics due to the nonlinearity of the loads, which are easy to cause resonance. Secondly, nonlinear The load is also an impact load. At the moment of arcing of the electric arc furnace, the start of the electric locomotive will form an impact on the power grid and easily stimulate the resonance of the distribution network.

Generally, resonance prevention and control can be roughly divided into two categories: one of the measures is to connect the damping resistor to increase the loop damping, which increases the loop damping and also increases the system loss during normal operation of the equipment; the second is to change the grid parameters, Destroy the parameter conditions of resonance at the frequency point where resonance occurs. This measure is only applicable to the situation where the operation mode of the power grid changes little and the parameter conditions of the power grid change little. If the operation mode of the power grid changes, the parameters of the power grid may move. At the resonant frequency point, resonance will appear again. Moreover, these two measures need to be implemented on the equipment where resonance occurs, that is, the above two measures can only be implemented on the equipment after the equipment that causes the resonance overvoltage accident must be correctly identified. Due to the large number of power grid equipment, the accident Analysis and identification are very difficult, so the implementation of measures is also difficult.

Utility model content

The technical problem to be solved by this utility model is to provide a resonance elimination isolation device connected in series with the distribution network feeder. Effectively isolate the resonance formed by each other with electrical equipment; solve the difficulties in the analysis, identification, and implementation of the existing resonance elimination measures, and the failure of the power grid operation mode. It has simple measures, convenient implementation, and adaptability. Strong features.

Technical scheme of the utility model:

A resonance elimination and isolation device connected in series with a distribution network feeder, the device includes a main inductance coil, and the main inductance coil is connected in parallel with a tuning element and a protection element to form an isolation and elimination device for resonating between a distribution network and electric equipment.

The tuning element includes a tuning inductor, which is connected in parallel with the first tuning capacitor after being connected in series with the second tuning capacitor and the tuning resistor.

The first tuning capacitor and the second tuning capacitor respectively adopt 30kV-180kV withstand voltage film dielectric capacitors.

The tuning inductance is made of an air-core coil made of an insulated winding coil, which is dipped in paint and potted.

The protection element is a zinc oxide arrester.

The main inductance coil is made of bare aluminum flat wire. It is an air-core coil with more than one layer connected in parallel without an iron core. The turns are insulated with glass fiber reinforced plastic pads, and the radial layers are separated by I-shaped stays.

The main inductance coil is clamped by the upper and lower hangers, and is fastened by several glass fiber reinforced plastic insulating screws and non-magnetic steel tie rods.

The turns of the main inductance coil are treated with insulating varnish and heat curing.

The resonance elimination isolation device connected in series with the distribution network feeder is characterized in that it includes the following measures:

1. The isolation and elimination device for resonance between the distribution network and the electrical equipment is connected in series on the power supply feeder between the distribution network and the user;

2. Through the tuning of the main inductance coil and the tuning element, an impedance is generated in the resonance frequency band, and the matching conditions of the parameters of the resonance are eliminated, so as to eliminate the resonance of the distribution network and the electrical equipment.

The beneficial effects of the utility model:

The utility model produces impedance on the resonance frequency band through the tuning of the main inductance coil and the tuning element T, and eliminates the parameter matching conditions of the resonance, which can effectively eliminate the resonance of the distribution network and the electrical equipment, and the utility model is not in The parameter condition is destroyed at a resonant frequency point, but its resonance condition is destroyed at a wide frequency range. Even if the parameters of the power grid change greatly, the coordination of the resonance parameters can be avoided. On the feeder, the resonance conditions of the power grid and the user are isolated, so that there is no need to identify the electrical equipment that causes resonance. Therefore, the utility model has the characteristics of simple measures, convenient implementation, and strong adaptability, and solves the problem of analysis and identification of existing resonance elimination measures. , Difficulties in implementation, and failures due to changes in grid operation.

Description of drawings

Fig. 1 is the principle structural block diagram of the present utility model;

Fig. 2 is the frequency impedance diagram of the device of the present invention.

Detailed ways

A resonance elimination isolation device connected in series with a distribution network feeder, which includes a main inductance coil 1, and the main inductance coil 1 is connected in parallel with a tuning element T and a protection element 2 to form an isolation and elimination device for resonating between a distribution network and electrical equipment.

By including the tuning of the main inductance coil 1 and the tuning element T, an impedance is generated in the resonant frequency band, and the parameter matching condition of the resonance between the distribution network and the electric equipment is eliminated, and the resonance between the distribution network and the electric equipment is effectively eliminated. The frequency impedance diagram of the device is shown in Fig. 2, which produces a higher impedance in the resonant frequency band, a low impedance for the power frequency current, and a low impedance for the high-frequency lightning current.

f1 is the upper limit frequency of the stop band;

f2 is the lower limit frequency of the stop band;

f0 is the geometric center frequency during tuning;

for blocking bandwidth

The tuning element T includes a tuning inductor 4. The tuning inductor 4 is connected in parallel with the first tuning capacitor 3 after being connected in series with the second tuning capacitor 5 and the tuning resistor 6. It forms a resonant circuit with the main inductance coil 1. It has a high impedance for the resonant frequency and a high impedance for the power frequency. The current is low impedance. Among them, the first tuning capacitor 3 and the second tuning capacitor 5 respectively use 30kV-180kV withstand voltage film dielectric capacitors, so that the device has a good insulation level, and the tuning inductor 4 is wound into an air-core coil with a high-insulation winding coil. Impregnation and potting treatment, with moisture-proof and high-voltage resistance.

The relationship between the parameters of each component is as follows:

Minimum blocking impedance for:

in is the inductance of the main inductance coil 1.

Capacitance of the first tuning capacitor 3 for:

in is the power frequency angular velocity, that is , 50Hz.

Tuning the inductance of inductor 4 for:

Capacitance of the second tuning capacitor 5 for:

From the above formula, it can be concluded that the impedance value of the device is extremely small at the power frequency, which does not affect the power transmission performance of the transmission line. In the high-frequency band of lightning waves, its impedance value is also extremely small, which will not affect the conduction of the microsecond-level lightning wave head on the feeder line, and will not affect the lightning protection performance of the line and substation.

The protection element 2 is a zinc oxide arrester, which limits the lightning overvoltage and operating overvoltage received by the device to a certain range, so as to protect the main inductance coil 1 and the tuning device T.

The main inductance coil 1 is made of bare aluminum flat wire, and is an air-core coil with more than one layer connected in parallel without an iron core. The turns are insulated with glass fiber reinforced plastic pads, and the radial layers are separated by I-shaped stays. The number of turns gradually decreases from the inner layer to the outer layer, and the cross section of the wire gradually increases from the inner layer to the outer layer, so that it has the characteristics of good heat dissipation, low eddy current loss, high mechanical strength, light weight, and small size. The inter-turns are insulated with glass fiber reinforced plastic pads, and the radial interlayers are spaced by I-shaped stays. After insulating varnish and heat curing treatment, the star frame at both ends of the coil is made of aluminum alloy extruded profiles, so that it has high mechanical strength. The characteristics of corrosion resistance and low loss; the main inductance coil 1 is clamped by the upper and lower hangers, fastened with several glass fiber reinforced plastic insulating screws and non-magnetic steel tie rods, and has good overall strength, insulation performance and anti-aging performance.

A resonance elimination isolation device connected in series with a distribution network feeder, characterized in that it includes the following measures:

1. The isolation and elimination device for resonance between the distribution network and the electrical equipment is connected in series on the power supply feeder between the distribution network and the user;

2. Through the tuning of the main inductance coil 1 and the tuning element T, an impedance is generated in the resonance frequency band, and the matching conditions of the parameters of the resonance are eliminated, so as to eliminate the resonance of the distribution network and the electrical equipment.

The utility model is based on the resonance principle. The condition for the resonance of the LC circuit is that the inductive reactance and the capacitive reactance in the loop are equal. When the power supply bus of the substation resonates, it means that the system inductive reactance and the capacitive reactance seen from the bus side are equal. An inductance element L is connected in series on the outlet side of the load feeder of the substation, which destroys the resonance condition in the loop. The inductance in series increases with the increase of frequency, and the inductance increases with the increase of frequency, and the capacitance with the increase of frequency decreases with the increase of frequency, so that The loop is inductive in the resonant frequency band, avoiding the resonance of the busbar. Therefore, the utility model has the following unique features: it can destroy the mutual resonance parameter coordination between the distribution network and the user equipment, and play the role of resonance isolation, especially It is the resonance caused by the cooperation between the user's electrical equipment and the grid parameters of the nonlinear load. It can destroy the coordination of resonance parameters in a wide resonance frequency band, and resonance will not occur under the constantly changing operating conditions of the power grid.

Claims (8)

1. the resonance being series at distribution network feeder eliminates spacer assembly; it comprises main inductive windings (1), it is characterized in that: main inductive windings (1) composes in parallel the isolation cancellation element of power distribution network and power consumption equipment resonance with tuned cell (T) and protection component (2).

2. a kind of resonance being series at distribution network feeder according to claim 1 eliminates spacer assembly, it is characterized in that: tuned cell (T) comprises tuning coil (4), tuning coil (4) is in parallel with the first tuning capacitance (3) after connecting with second tune electric capacity (5) and tuning resistor (6).

3. a kind of resonance being series at distribution network feeder according to claim 2 eliminates spacer assembly, it is characterized in that: the film capacitor that the first tuning capacitance (3) and second tune electric capacity (5) adopt 30kV-180kV withstand voltage respectively.

4. a kind of resonance being series at distribution network feeder according to claim 2 eliminates spacer assembly, it is characterized in that: the hollow coil that tuning coil (4) turns to for insulation winding coil forms through dipping lacquer and embedding process.

5. a kind of resonance being series at distribution network feeder according to claim 1 eliminates spacer assembly, it is characterized in that: protection component (2) is zinc oxide arrester.

6. a kind of resonance being series at distribution network feeder according to claim 1 eliminates spacer assembly, it is characterized in that: main inductive windings (1) forms for naked flat aluminium wire coiling, for the hollow coil of one deck more parallel iron-core-free, turn-to-turn fiberglass pad insulation, with I-shaped stay interval between radial layer.

7. a kind of resonance being series at distribution network feeder according to claim 1 eliminates spacer assembly, it is characterized in that: main inductive windings (1) clamps with upper and lower suspension bracket, have some glass fibre reinforced plastic insulating screw rods and non-magnetic steel pull bar fastening.

8. a kind of resonance being series at distribution network feeder according to claim 1 eliminates spacer assembly, it is characterized in that: main inductive windings (1) turn-to-turn is through insulation dipping lacquer and hot curing process.