300 kVA DVR 200V Responds in 2 ms at Zhongjing Semiconductor
Critical Production Loads Continued Operating Without Alarms During a 396 ms Voltage Sag
Shanghai Wenzheng Electric Co., Ltd. is a manufacturer of dynamic voltage restorers. For this project, Wenzheng Electric designed, manufactured, and configured a 300 kVA dynamic voltage restorer based on Ningxia Zhongjing Semiconductor’s 200 V power system, 175 kW critical load, and one-second ride-through requirement.
In August 2023, lightning caused a three-phase voltage sag on the incoming supply. The event lasted 396 ms and exceeded 40% sag depth. The dynamic voltage restorer completed compensation in approximately 2 ms and maintained the load-side voltage above 90% of the reference level shown in the event record. Throughout the event, the production equipment continued operating without alarms or shutdowns, and the monocrystalline silicon growth process was not interrupted.
Product information: 208 V Dynamic Voltage Restorer
Project Specifications
| Item | Specification |
|---|---|
| Industry | Semiconductor materials manufacturing |
| Production process | Growth of 8-inch semiconductor-grade monocrystalline silicon ingots |
| Site system voltage | Three-phase 200 V line-to-line; approximately 115 V line-to-neutral |
| Critical load | Approximately 175 kW |
| Dynamic voltage restorer capacity | 300 kVA |
| Project equipment model | DVR-330300 |
| Energy storage | Supercapacitors |
| Configured ride-through duration | 1 second |
| Compensation response time | Approximately 2 ms |
| Installation date | May 2023 |
The facility operates a three-phase 200 V line-to-line system. The 115 V values shown in the waveform record are line-to-neutral measurements. The DVR is compatible with the 208 V voltage class listed on the product page and was configured for the site’s 200 V system.
The Customer’s Voltage Sag Risk
Ningxia Zhongjing Semiconductor produces 8-inch semiconductor-grade monocrystalline silicon ingots. The silicon growth process is continuous, and equipment such as heating power supplies, vacuum pump sets, mechanical drives, water-circulation controls, and variable frequency drives is sensitive to power-quality disturbances.
A short voltage sag can trigger undervoltage protection in variable frequency drives, reset controllers, or stop equipment. Even if the utility supply recovers quickly, an interrupted production process may have to be restarted, resulting in lost production time and work-in-process losses.
Wenzheng Electric’s Solution
Wenzheng Electric selected the system based on the site’s load composition, inductive-load inrush, required voltage sag depth, and ride-through duration. The final configuration used a 300 kVA DVR-330300 dynamic voltage restorer with a one-second ride-through duration and supercapacitor energy storage.
The dynamic voltage restorer was installed upstream of the critical loads to continuously monitor the three-phase supply:
- Under normal grid conditions, the utility supplies the load while the DVR remains synchronized and ready.
- When a voltage sag is detected, the DVR responds rapidly and supports the load-side voltage.
- After the grid recovers, the system automatically ends compensation and returns to standby.
The project demonstrates Wenzheng Electric’s engineering capabilities in dynamic voltage restorer design and manufacturing, 200 V and 208 V voltage adaptation, inductive-load analysis, system sizing, supercapacitor configuration, and millisecond-level voltage compensation.
Recorded Voltage Sag Event
The event occurred on August 1, 2023, at 09:21:16. Lightning on the supply side caused a three-phase voltage sag with a maximum duration of 396 ms.
| Phase | Grid-Side Voltage | Grid-Side Percentage | Compensated Load-Side Voltage | Load-Side Percentage |
|---|---|---|---|---|
| Phase A to neutral | Grid-Side Voltage: 70.4 V | Grid-Side Percentage: 59.0% | Compensated Load-Side Voltage: 110.5 V | Load-Side Percentage: 90.0% |
| Phase B to neutral | Grid-Side Voltage: 74.3 V | Grid-Side Percentage: 62.2% | Compensated Load-Side Voltage: 114.6 V | Load-Side Percentage: 93.4% |
| Phase C to neutral | Grid-Side Voltage: 74.3 V | Grid-Side Percentage: 62.2% | Compensated Load-Side Voltage: 114.3 V | Load-Side Percentage: 93.1% |
All three grid-side phase voltages dropped significantly. Phase A reached the lowest level at 59.0% of the reference value shown in the event record. After the dynamic voltage restorer responded, all three load-side phase voltages remained above 90%.
Waveform Analysis: The Sinusoidal Waveform Remained Intact Despite an Approximately 2 ms Gap
The upper waveform shows the three-phase grid-side voltage, while the lower waveform shows the compensated three-phase load-side voltage. When the voltage sag occurred, the grid-side waveform amplitude decreased significantly. After the dynamic voltage restorer responded, the load-side waveform remained close to its normal sinusoidal amplitude.
At the point where the sag was detected and compensation began, the load-side waveform showed a brief gap of approximately 2 ms. This gap corresponds to the DVR’s sag detection and compensation response interval. After this brief transition, the three-phase sinusoidal waveform remained continuous and intact, with no prolonged power interruption or waveform loss. The protected load continued operating normally without alarms.
Project Results
- The DVR successfully protected the load through a 396 ms three-phase voltage sag exceeding 40% depth.
- When the grid-side voltage fell to as low as 59.0%, the load-side voltage remained above 90%.
- Voltage compensation was completed in approximately 2 ms while the overall three-phase sinusoidal waveform remained intact.
- The 175 kW critical process load continued operating without alarms or shutdowns.
- Production of 8-inch semiconductor-grade monocrystalline silicon ingots was not interrupted.
This field event demonstrates that a dynamic voltage restorer manufactured by Wenzheng Electric can provide fast voltage sag protection for continuous semiconductor production loads. The Winzele DVR protected the customer’s critical process during an actual lightning-related grid disturbance.
Frequently Asked Questions
Why was a 300 kVA dynamic voltage restorer selected for a 175 kW load?
The protected system includes heating power supplies, vacuum pump sets, mechanical drives, and variable frequency drives. System sizing therefore considered not only the rated power but also inductive-load inrush, voltage sag depth, and the required one-second ride-through duration. Based on these requirements, a 300 kVA dynamic voltage restorer was selected.
Why does the product page specify 208 V when the project operates at 200 V?
200 V is the actual line-to-line voltage at the project site, while 208 V is the standard voltage class used for this product series. The equipment is compatible with both applications and was configured for the site’s 200 V system.
Did the approximately 2 ms waveform gap affect the protected load?
No. The brief gap occurred while the DVR detected the sag and initiated compensation. The three-phase sinusoidal waveform remained intact after the transition. During the actual event, the protected equipment continued operating without alarms or shutdowns.
About the Manufacturer
Shanghai Wenzheng Electric Co., Ltd. manufactures dynamic voltage restorers for semiconductor production, precision manufacturing, automated production lines, and other sensitive industrial applications. System capacity, voltage class, sag protection depth, and ride-through duration can be configured according to the site’s electrical system and critical-load requirements.
For project selection, please provide the system voltage, load capacity, load type, minimum residual voltage, and required ride-through duration. For more information, visit the dynamic voltage restorer product page.
Related Product
Dynamic Voltage Restorer (DVR): Winzpower DVR systems provide voltage-sag compensation on the low-voltage side of a protected feeder or process transformer, so the protected load is supported through the specified sag depth and support duration.
