1. Purpose
GZX series inductive resistance current-limiting reactors (hereinafter referred to as current limiters) are connected in series with the parallel capacitor bank, as a supporting equipment to limit the closing inrush current of the parallel capacitor bank and eliminate the effect of the capacitor discharge current when the power system is short-circuited.

2, principle and function
1. Working principle of current-limiting reactor
The current-limiting reactor (hereinafter referred to as the current limiter) is composed of the CKDK type low inductance dry-type air-core series reactor (hereinafter referred to as the reactor) and the QR type damping resistor with graphite electrodes (hereinafter referred to as the damper). Its working principle is to comprehensively use the reactor to present high impedance to the high-frequency inrush current when the shunt capacitor bank is put into the grid to limit the amplitude of the inrush current and the damping resistance to consume oscillation energy to accelerate the attenuation of the inrush current. The addition of graphite electrodes utilizes the spark gap so that the damping resistor is only connected to the circuit when the capacitor bank is put into the grid. With the rapid decay of the inrush current, the voltage at both ends of the reactor drops, the graphite gap automatically extinguishes the arc, and the damping resistor is scattered, thereby avoiding the power consumption caused by the long-term connection of the damping resistor. Therefore, the working principle and composition of the current limiter and the commonly used series reactor are significantly different.
2. Current-limiting reactor function
2.1 A good current limiting effect can be obtained.
2.2 It can eliminate the influence of the discharge current of the large-capacity parallel capacitor device on the short-circuit current of the system.
2.3 It can reduce the overvoltage level when the circuit breaker has a heavy breakdown and reduce the probability of multiple heavy breakdowns.

3, model and classification
1. Model meaning:

2. product category

2.1 The voltage grade of the product is divided into 6kV, 10kV, two kinds.

2.2 The main products of the 6kV class have four rated currents of 100A, 200A, 400A, and 600A.

2.3 The main products of 10kV and 35kV class have four kinds of rated current: 160A, 250A, 400A, 600A.

2.4 The main products of the 10kV and 35kV grades have four rated currents of 160A, 250A, 400A, and 600A.

2. 5 Special specifications of 6kV, 10kV, 35kV current limiters can be customized.

4 structural characteristics
1. The inductance resistance current-limiting reactor is composed of two parts: reactor and damper.

2. The reactor is a dry hollow structure, the coil is wound with high-quality bare copper wire or aluminum wire, the glass fiber block is inserted between the turns, and the entire coil is fastened with non-magnetic clips to meet certain mechanical strength and dynamic thermal stability requirements. The product allows long-term operation at 1.3 times the rated current and has the advantages of low energy consumption, low investment and easy maintenance.

3. The damping resistor is air-cooled and assembled with plate-shaped resistance elements. The damping resistor is placed inside the reactor coil and has a compact structure with good electrical performance and mechanical strength.

4. The graphite electrode can be adjusted flexibly, and the center of the two spherical polar axes (that is, the non-concentricity) does not exceed 2mm.

5. Main technical performance
1. Rated parameters

Table 1, 6kV series current limiter rated parameters

Table 2, 10kV series current limiter rated parameters

Table 3. Rated parameters of 35kV series current limiter

2. Thermal stability

The reactor can withstand 25 times the rated current (power frequency) for 2s. The temperature of the conductive part cannot exceed 250°C without any thermal and mechanical damage.

3. Dynamic stability

3.1 The reactor can withstand the action of 2.5×25 times the rated current (power frequency) for a duration of 0.2s without causing electrical flashover breakdown, breakdown and mechanical damage.

3.2 Reactors and dampers allow high-frequency attenuation discharge currents of 15kA (peak) and 10kA (peak) respectively, without electrical flashover, breakdown and mechanical damage.

4. Overcurrent

When the effective value of the combined current of the current limiter does not exceed 1.3 times the rated current under the action of the fundamental wave and harmonic current, the current limiter can operate continuously.

5. Temperature rise

When the reactor is subjected to temperature rise test, its temperature rise does not exceed the temperature rise limit of 70K, and the hottest spot temperature does not exceed 130°C (Class B insulation).

6. Insulation level

The insulation level of the current limiter installed on the insulating stand meets the requirements of Table 4. Table 4

Installation and acceptance
1. See Figure 1 for the principle wiring of the current limiter and the parallel capacitor bank.

2. Figure 2 shows the outline size diagram of 6kV and 10kV current limiters.

3. The outline dimension diagram of the 35kV current limiter is shown in Figure 3

4. The current limiter should be installed on an insulated platform, and its insulation level to the ground should be consistent with the insulation level of the connected power grid. If the current limiter is connected to the power side of the capacitor bank in series, it should be installed in phases. If the current limiter is connected in series on the neutral side of the capacitor bank, it can be installed in phases or on the same insulating platform.

5. Setting of spark gap: The setting value of spark gap breakdown voltage is 1800~2500V (gap distance is about 1~2.0mm), and the operating voltage is based on the average value of three times.

6. Installation and use conditions

6.1 Installation environment: indoor.

6.2 Ambient temperature: -40℃～+45℃.

6.3 Altitude: ≤1000m.

6.4 Relative humidity: daily average relative humidity ≤95%, monthly average relative humidity ≤90%.

6.5 Maximum wind speed: 35m/s.

6.6 Seismic requirements: the maximum earthquake intensity is 8 degrees.

6.7 Installation site: There should be no harmful gas, vapor, conductive or explosive dust.

7. See Table 5, Table 6, and Table 7 for the matching specifications of the current limiter and parallel capacitor bank.

Table 5 Selection table of current limiter specifications for 6kV (phase voltage 6.6/√3kV) parallel capacitor device

Table 6 Selection table of current limiter specifications for 10kV (phase voltage 11/√3kV) class shunt capacitor device

Table 7 Selection of current limiter specifications for 35kV (phase voltage 38.5/√3kV) parallel capacitor device

Figure 1. Wiring principle and method of current limiter and parallel capacitor bank

Figure 2. Schematic diagram and dimensions of 6kV and 10kV current limiters

Figure 3. Schematic diagram and dimensions of 35kV current limiter

The company's product quality is guaranteed, reliable in use, GZX inductance resistance type current-limiting reactor and capacitor device are well matched, the price is favorable, and the service is thoughtful. We warmly welcome users from inside and outside the province to call or write to the company.