HuiZhou Antenk Electronics Co., LTD , https://www.atkconn.com
Problems in the installation and operation of the transformer
There are numerous challenges in the installation and operational management of transformers, with frequent incidents such as transformer burnouts and arrester explosions. Traditionally, arresters have been installed on the upper side of the high-voltage fuse. However, based on practical experience, this method is not optimal. The following discussion presents the author’s insights for reference by peers.
1. Arrester Installation
1.1 Issues with Current Installation
The arrester is typically placed above the high-voltage fuse, which, according to regulations, requires the base height to be at least 2.5 meters from the ground. This setup makes it difficult to replace or repair the arrester without causing a power outage on the 10kV line. Additionally, the grounding lead is too long, failing to meet technical standards. To address these issues, the arrester was relocated to the lower side of the high-voltage fuse. This change maintains the protective function while making maintenance more convenient, reducing the frequency of outages. Moreover, when the arrester degrades due to lightning strikes, the increased power frequency current can cause the fuse to blow, isolating the fault and minimizing the risk of single-phase grounding or short-circuit tripping, thus improving power supply reliability.
1.2 Installation Recommendations
The arrester should be installed at least 0.7 meters away from the fuse to ensure safe working distance during maintenance. The lead length should be minimized for reliability, using 35–50 mm² black insulated cable to reduce reactance and residual voltage. The distance between the arrester and the transformer should exceed 2 meters to increase inductance and enhance the transformer's lightning resistance. When removing or installing the arrester, special fixtures must be used instead of wires to prevent flashover. The grounding conductor must be securely connected to the crossarm and pole to avoid grounding faults or damage to the transformer in case of an explosion.
2. Operational Challenges of Arresters
2.1 Due to damage, breakdown, rust, and difficulty in installation, funding and cost constraints make it hard to maintain and replace arresters. Additionally, village electricians often lack sufficient responsibility, leading to delayed or missed installations. As a result, the installation rate remains low, and many systems remain unprotected.
2.2 Many arresters have not been tested for years due to the large workload involved in regular calibration, leaving non-functional units still in operation.
2.3 Poor installation practices by construction and maintenance staff result in loose, tilted, or incorrectly positioned arresters, along with abnormal lead connections.
2.4 Some arrester products are of poor quality, offering inadequate protection against lightning surges.
2.5 Grounding leads often show broken strands or entanglement, and some are even replaced with ordinary wires. Most have high grounding resistance, further compromising safety.
3. Improvement Measures
3.1 Increase public awareness to emphasize the importance of arrester installation.
3.2 Train electricians to master proper installation procedures and ensure standardized work.
3.3 Strengthen operational management through regular inspections, testing, and verification. Any substandard arresters must be taken offline.
3.4 Promote the use of zinc oxide arresters for better performance.
3.5 Conduct thorough inspections of all distribution transformers’ arrester grounding bodies and transformer grounding systems, ensuring that grounding resistance is properly addressed.