Introduction to automatic step voltage regulator | Sefon electrical
The automatic step voltage regulator is an intelligent voltage regulation unit connected in series to the mid-to-late sections of 6–35 kV distribution lines or the outgoing side of substations. It is specifically designed to address issues such as unstable voltage at line endpoints and undervoltage/overvoltage caused by long-distance transmission and large load fluctuations. The device can monitor line voltage in real time and automatically adjust the transformer tap ratio without power interruption or manual intervention, maintaining the output voltage within the national standard compliance range of ±7% of the rated voltage. It is a key equipment for improving power quality and enhancing the reliability of distribution networks.
application scenarios
The automatic step voltage regulator is widely applicable to rural and remote power grids, long-distance feeders in mountainous areas, industrial parks, mines, and large residential complexes. It is particularly suitable for distribution systems with a wide supply radius, high line losses, and frequent voltage fluctuations. The device can effectively prevent issues such as motor underperformance or equipment damage caused by undervoltage, as well as insulation aging and increased energy consumption caused by overvoltage.
Working principle
The automatic step voltage regulator operates based on the principle of electromagnetic voltage regulation of an autotransformer combined with automatic switching of the on-load tap changer. Its core components include an autotransformer, an on-load tap changer, an automatic controller, and an outdoor cabinet, forming a closed-loop control logic of "sampling - comparison - regulation - stabilization."
- Real-time Voltage Sampling: Voltage and current signals on both the input and output sides of the line are continuously collected 24/7 via potential transformers (PTs) and synchronously transmitted to the automatic controller.
- Deviation Analysis and Decision-Making: The automatic controller, centered on a high-performance microcontroller, compares the sampled voltage with a preset reference value (e.g., 10 kV) to calculate voltage deviation. If the voltage falls below the lower limit, a boost command is issued; if it exceeds the upper limit, a buck command is triggered; if within the acceptable range, the current tap position is maintained.
- On-Load Automatic Voltage Regulation: The controller drives the three-phase on-load tap changer to switch between different taps of the autotransformer's series winding (typically 7–17 taps, each adjusting 2.5%–3% of the rated voltage). This changes the transformer turns ratio and, through electromagnetic induction, adds or subtracts part of the voltage to achieve precise output voltage correction.
- Stabilized Output and Protection: After voltage adjustment, the output voltage is continuously monitored to form a closed-loop feedback, ensuring voltage remains within the set range. The system also provides comprehensive protection functions, including overcurrent, overvoltage, undervoltage, and overheating. In the event of a fault, it automatically issues alarms or trips to safeguard both the equipment and the line.
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Seamless Bypass Switching: Equipped with a bypass disconnector, the device can seamlessly switch to bypass operation during maintenance or shutdown without interrupting power supply, ensuring continuous electricity delivery.
features
- Compact size, high capacity, and lightweight design, enabling easy installation and commissioning.
- Delivers significant energy-saving and loss-reduction performance.
- Adopts an autotransformer configuration featuring low losses and high operating efficiency.
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Provides a wide voltage regulation range with remarkable regulation performance and high voltage regulation accuracy.