Application of Reactors in Long-Distance Transmission Grids: Reactive Power Compensation and Overvoltage Suppression Solutions

Rockwill

17yrs 700++ staff 108000m²+m² US$150,000,000+ China

Application Scenario:
Excessive capacitive charging power in long-distance transmission lines of 500kV substations.

Problem Background:
In long-distance transmission lines rated at 500kV and above, the line-to-ground capacitance effect is significant. When operating under light load or no load, these lines generate substantial capacitive charging power (capacitive reactive power). This excessive power leads to:

Power-frequency overvoltage: Line voltage rises significantly, potentially exceeding equipment insulation withstand levels and jeopardizing grid security.
Voltage fluctuations and stability issues: Degrades power quality, increases line losses, and constrains line transmission capacity.
System reactive power imbalance: Makes it difficult to maintain system voltage within qualified ranges.

To address these issues, high-performance shunt reactors must be installed at key nodes (e.g., at both ends or mid-line 500kV substations) for inductive reactive power compensation, absorbing the excess capacitive charging power.

Core Solution: BKLG-500 Shunt Reactors
For mitigating excessive charging power in 500kV long-distance lines, we recommend employing BKLG-500 oil-immersed shunt reactors with iron cores as the core solution.

Key Equipment Features and Technical Advantages:

Efficient Absorption of Capacitive Reactive Power:

Rated Capacity: 60 Mvar. Meticulously matches long-line charging power requirements, effectively absorbing excess capacitive reactive power generated by the line.
Function: Balances line reactive power, confines voltage fluctuations within safe and stable ranges, and significantly suppresses power-frequency overvoltage during light/no-load conditions.

Exceptional Reliability and Overload Capacity:

Temperature Rise Limit: 55°C (under rated conditions). Utilizes advanced insulation materials and cooling design to ensure long-term operational reliability.
Overload Capability: Can operate continuously for 30 minutes at 110% of rated capacity. This design effectively withstands system short-term surges or abnormal conditions (e.g., load rejection), providing an additional safety margin for the grid and ensuring equipment security.

Ultra-Low Noise and Vibration Design:

Special Magnetic Shunt Structure: Optimizes core magnetic circuit design, drastically reducing vibration and noise caused by core magnetostriction.
Guaranteed Sound Pressure Level: Operating noise ≤ 65 dB(A). This performance significantly surpasses conventional products, meeting stringent environmental requirements, making it especially suitable for substations near residential areas or noise-sensitive zones.

Robust Construction and Stable Performance:

Iron Core Design: Offers structural robustness, high mechanical strength, strong short-circuit withstand capability, low no-load loss, and excellent capacity adjustment characteristics.
Oil-Immersed Cooling: High heat dissipation efficiency, superior insulation performance, easy maintenance, and proven reliable technology.

Scheme Benefits:

Effectively suppresses power-frequency overvoltage: Maintains line voltage within safe limits, protecting critical equipment like transformers, circuit breakers, and surge arresters.
Significantly improves voltage stability and quality: Balances system reactive power, reduces voltage fluctuation range, and enhances power supply reliability and quality.
Increases line transmission capacity: Reduces limitations on transmission capacity caused by excessively high voltage.
Enhances system operational safety margin: Robust overload capability copes with contingencies.
Meets environmental requirements: Low-noise design minimizes impact on surrounding environment.

Implementation Results:

Significant reduction in voltage fluctuations: Voltage fluctuation range for the associated line was successfully controlled to within ±2%, compared to ±8% pre-implementation.
Effective elimination of overvoltage risk: Power-frequency overvoltage under light load and no-load conditions was effectively limited below equipment safety thresholds.
Stable and reliable operation: The BKLG-500 reactors have operated stably since commissioning. Measured noise values are significantly lower than guaranteed levels, earning high user recognition.