CKSG Series Low-Voltage Series Reactor

Application
The CKSG series dry-type iron-core series Reactors are used in low-voltage Reactive Power Compensation cabinets and are connected in series with Capacitors. In low-voltage power networks with numerous harmonic sources such as rectifiers and converters, the resulting higher-order harmonics can seriously endanger the safe operation of main transformers and other electrical equipment. When connected in series with capacitors, the reactor can effectively absorb grid harmonics, improve system voltage waveform, enhance the system power factor, suppress inrush currents and operational overvoltages, and ensure the safe operation of capacitors.

Operating Environment

• Altitude: not exceeding 2000 meters;

• Ambient temperature: -25 to +45°C, relative humidity ≤ 90%;

• Free from harmful gases, flammable, or explosive substances;

• The surrounding environment should have good ventilation. If the series reactor is installed inside a cabinet, additional ventilation equipment should be provided.

Technical Parameters

• Applicable for 400V and 660V systems;

• Reactor types: 6%, 7%, 14%, etc.;

• Rated insulation level: 3kV/1min;

• Temperature rise limits: core ≤ 85K, winding ≤ 95K;

• Noise level: ≤ 45dB;

• Continuous operation at 1.1 to 1.35 times rated current;

• Reactance linearity: the ratio of reactance at 1.8 times rated voltage to reactance at rated current ≥ 0.95;

• Phase-to-phase reactance deviation: ≤ ±3%;

• Temperature class: H (≥ 180°C).

Selection and Considerations for Low-Voltage Series Reactors
The capacitor is the core component of a reactive power compensation system. Improper selection of capacitor parameters can directly affect the service life and performance of the entire system; therefore, parameter selection must be carried out with great care.

• Rated capacitor voltage should generally be higher than the maximum operating voltage and account for voltage fluctuations, voltage rise across the capacitor after series reactor connection, bus voltage rise after capacitor energization, and harmonic voltage superposition, to ensure long-term safe and reliable operation.

Series Reactor Selection Guidelines

• For limiting inrush current only: select a reactor of 1% of capacity;

• When the grid harmonics are dominated by the 3rd harmonic and above (3rd harmonic content exceeds limits): select a 12%-13% series reactor;

• When the grid harmonics are dominated by the 2nd and 5th harmonics (high 5th harmonic content): select 4.5%, 6%, or 7% series reactors; do not use a 1% reactor.

Installation Recommendations

• For operating capacitor systems: series reactors cannot be arbitrarily combined with capacitors; harmonic conditions at the connection point must be considered.

• For new substations: the suitability of series reactors must be verified by calculation and field assessment; the capacity of capacitor banks should not be arbitrarily increased or decreased when reactors are properly selected.