Long-Term Reliability Design of High-Voltage Doorknob Capacitors in Coupling Devices
High-voltage coupling devices are often deployed in harsh, maintenance-prone environments such as substations and transmission lines. Their core component, the coupling capacitor, must withstand continuous electrical stress, temperature cycling, and potential transient overvoltage surges. Any premature failure could lead to communication interruption or monitoring system failure, with serious consequences. The long-term reliability and robust design of high-voltage door handle capacitors are the cornerstones of ensuring trouble-free operation of the entire system.

Harsh Operating Conditions for Capacitors in Coupling Devices

Continuous high-voltage stress: Capacitors operate under the electric field of rated power frequency voltage and its harmonics for extended periods, continuously testing the dielectric strength of the dielectric.

High-frequency current and thermal stress: Carrier signal current flows through the capacitor, causing dielectric loss and resulting in temperature rise, especially when the signal power is high.

Environmental stress: Outdoor devices must withstand environmental factors such as daytime temperature fluctuations, humidity, ultraviolet light, and even pollution.

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Xian Xiwuer Electronic & Info. Co., Ltd. is a wholly state-owned company with a registered capital of 91.46 million RMB Yuan, owning a total assets of 315 million RMBYuan, under the jurisdiction of Xi'an State-owned Assets Supervision & Management Committee. There are about 400 employees, with an annual sales income of 250 million RMB Yuan.

The main products include Zinc Oxide Varistors, thermistors, H-V ceramic capacitors, SPD, and Solar Energy Surge Protective Devices. The company has advanced production equipment, including 18 large sintering furnaces, 8 automatic assembly lines, the largest energy impulse current generator and a series of special test equipment and environmental test equipment. In the same industry in China, the company has the largest production capacity and the highest degree of automation with the most complete testing methods.

Our employees are 8 with master's degrees and more than 80 engineers with senior technical titles. 12 technicians have been awarded Experts with Outstanding Contributions by the Xian municipal government, and 1 expert has been enjoying a special allowance from the State Council.

The company has five sites for business production and operation, covering an area of 50,000 square meters. Its construction area is up to more than 54,000 square meters.

· No.99, Fengqing Road, Lianhu District, Xi an(ceramic capacitor)

· No.1118, Ziqaing Road, Xincheng District, Xi' a (Headquarters, varistors, thermistors)

· No.11, Longshou South Road, Lianhu District, Xi' a (Registration, photovoltaic lightning protection box)

· Block A, No.18, Gaoxin Road, High-tech District, Xi' an

· Jinghe New Town Xi Xian New Area(the new plant)

• Xian Xiwuer Electronic and Info. Co., Ltd. is a wholly state-owned company with a registered capital of CNY 101.465 million (exchanged to USD 15.85 million), owning total assets of CNY315 million (traded to USD 49.22 million). It was established in 1976. Currently, it has about 460 employees, with an annual sales income of CN280 million (exchanged to USD43.75 million). The company has four production and business bases covering an area of 43052 square meters, and a construction area of more than 50000 square meters. The company has 8 persons with master's degrees, more than 80 engineers with senior technical titles 12 technicians who have been awarded Experts with Outstanding Contributions by the Xian municipal government, and 1 expert who has been enjoying a special allowance from the State Council.

• The main products include

            • Smart Embedded Epoxy Pole；

            • Integrated Instrument Transformer

• Capacitive Voltage Divider；

• High Voltage Capacitor Rod；

• High Voltage Film Capacitor；

• High Voltage Resistor；

• Primary and Secondary Integrated Intelligent assembly and components with the function of voltage measurement, current measurement, protection, temperature monitoring, and power supply；

• Medium-High Voltage components/parts/ assembly；

• Surge Protective Device for Power Supply System；

• Chips for lightening devices；

• Zinc Oxide Varistor；Thermistor.

Major Customers: ABB, Schneider, GE, ZTE, XD Electric, XJ Electric, PingGao Electric and etc.

• The company has the provincial Technical R&D Center. The company has developing and manufacturing experiences of the key products HV Ceramic Capacitor, SPD, Varistor, Thermistor and for nearly 20 years. There have been 32 patented technologies, 4 invention patents, and 4 national key new products. The company is in the leading position in the same industry. The company has grown very fast with a unique management system which is the fundamental guarantee to the continuous development of the enterprise under the state-owned system. In Northwest China, the company is the first to implement ISO 9001 standards and the first to promote the use of ERP management systems, having achieved ISO9001, ISO14001, and ISO45001 approval, thus standardizing and improving the management level of the company.
• Through continuous technological innovation, product R&D, and quality improvement the main technical performance and reliability of the products are at the internationally advanced level the same level as Panasonic and Siemens. The products have UL, VDE, TUV, CAS, CE, CQC, RoHS, and REACH certifications. The company has advanced production equipment among which the key production equipment and modern assembly lines are imported from Japan, the U.S.A, Germany, Korea, and Belgium including 26m large sintering tunnel furnaces8 automatic assembly lines, the largest energy impulse current generator and a series of special test equipment and environmental test equipment. In the same industry in China, the company has the largest production capacity and the highest degree of automation with the most complete testing methods. The company has two routine test laboratories with the most advanced lightning testing equipment and environmental testing equipment which comply with national standards for laboratory construction. They are the significant laboratories supported by Shaanxi Province with professional testing technicians undertaking part of the supervision and inspection of electronic products in Shaanxi Province at the same time.
• We believe we are able to supply satisfied goods and services to customers at home and abroad with the most reasonable price and the shortest delivery time. on the basis of our excellent quality assurance capacity, technical development capacity, and rich manufacturing experiences.

Through continuous technological innovation, product R&D, and quality improvement, the main technical performance and reliability of the products are at the international advanced level, at the same level as Panasonic and Siemens. The products have UL, VDE, TUV, CAS, CE, CQC, RoHS, and REACH Certification