What Are Common Faults in Power Distribution Lines? A Complete Guide to Operational Challenges and Solutions

1 Overview of Power Transmission and Distribution Lines

1.1 Key Characteristics of Power Transmission and Distribution Lines

• High Maintenance Difficulty: This is mainly due to the wide area covered by power transmission and distribution lines, the harsh terrain of the laying areas, and the impact of seasonal climate changes, all of which contribute to difficult maintenance.

• High Requirement for Operational Reliability: The reliable operation of power transmission and distribution lines is closely related to the development of industry and agriculture. To meet the needs of all sectors of society, power grid companies impose stricter management requirements on their operational reliability, which determines their characteristic of extremely high operational reliability.

• Prominent Safety Hazards: Similarly, the wide coverage of the lines leads to potential hazards caused by different environmental influences, resulting in the characteristic of prominent safety hazards.

1.2 Common Fault Types of Power Transmission and Distribution Lines

• External Force-Related Faults: Generally, external force is the most common and major cause of faults. Data shows that damage to power transmission and distribution lines caused by external forces accounts for half of all damage factors.

• Human-Related Faults: In most cases, human-related faults are caused by operational errors, which is also an important factor leading to damage to power transmission and distribution lines.

• Equipment-Related Faults: Some equipment may experience faults or damage after a period of use due to quality or performance issues.

2 Major Issues Affecting the Safe Operation of Power Transmission and Distribution Lines

2.1 External Damage Factors

According to relevant statistics, damage to power transmission and distribution lines in the power grid caused by external damage is increasing year by year, mainly manifested in the following aspects:

• Blasting operations for mountain development in mountainous areas damage line insulators or even cut off the lines.

• Flames and thick smoke from open-air burning in rural areas damage the insulation layer of the lines, causing line tripping.

2.2 Unreasonable Line Network Structure

With the continuous expansion of distribution network construction and the increasing load of distribution network lines, the lines cannot be adjusted in a timely and effective manner. This is generally reflected in the following:

The cross-sectional area of conductors (especially the cross-sectional area of conductors at the starting end of some lines) is too small, resulting in inability to transmit electricity even when power is available, and even fuse melting of line leads.

Some branch lines are connected to more than a dozen distribution transformers, leading to large load capacity. This often causes overloading of the branch lines during operation, resulting in power outages and blackouts.

Some lines are too long but lack necessary branches, leading to increased line losses and reduced voltage at the end of the lines, which in turn affects the quality of the power supply voltage.

2.3 Lightning Strike Factors

Thunderstorm weather is common in most regions of China. Under the thermal effect and mechanical force of lightning, power transmission and distribution lines are prone to flashovers, which cause severe damage to the power transmission and distribution line system and affect its normal operation. In addition, the overvoltage generated by lightning strikes is transmitted to the power supply equipment in the power system through the power transmission and distribution lines. Under the action of overvoltage, the normal dielectric strength of the power supply equipment is impaired, and electronic components in some sensitive power supply equipment in the power grid are damaged, undermining the safety and stability of the substation system.

2.4 Aging of Power Transmission and Distribution Lines and Equipment

In China, most equipment in the transmission and distribution network is outdated, which makes the power transmission and distribution lines and equipment unable to effectively meet the requirements for the stable operation of the power grid. This is mainly reflected in the following:

The operating mechanisms of most pole-mounted circuit breakers are unreliable, and the operation methods are relatively backward, making it impossible to implement effective remote operation.

There are low-quality insulated wall bushings in the distribution network, which may break down under the action of various overvoltages, causing permanent line faults.

Some surge arresters of poor quality are used in the transmission and distribution network, which are prone to explosion when subjected to overvoltage, leading to distribution network faults.

3 Difficulties in the Operation and Maintenance of Power Transmission and Distribution Lines

As a complex system, the power system network has made the operation and maintenance of power transmission and distribution lines more complex with the continuous development of smart grid construction. This is because the power transmission and distribution lines cover an extremely wide area, and the geographical environment varies in different regions, which in turn has different impacts on line installation. In many areas, severe climate problems (such as cold winters and hot summers) affect the operation of power transmission and distribution lines.

There are also difficulties in the design, laying, and maintenance of power lines. For example, in relatively remote areas, trees growing near power transmission and distribution lines may pose a threat to line safety; the continuous growth of trees may come into contact with the erected lines, triggering power safety faults. When the temperature rises, the sag of the conductors increases, which may also lead to faults in the power network.

The increasingly developed industry and agriculture have also raised higher requirements for power transmission and distribution. Therefore, ensuring the stability and reliability of power transmission, increasing transmission capacity, and maximizing the improvement of operation quality are also major challenges faced by current power workers.

4 Countermeasures for the Operation and Maintenance of Power Transmission and Distribution Lines

Improve the Safety Early Warning System for Power Transmission and Distribution Lines: Due to China’s topographic and climatic characteristics, there are many difficulties in the maintenance of power transmission and distribution lines. Therefore, it is necessary to establish an early warning system for power transmission and distribution lines based on actual conditions to identify existing problems and take effective solutions.

To address the difficulties in the operation and maintenance of power transmission and distribution lines caused by geographical or climatic factors in China, modern scientific and technological means should be adopted to establish a corresponding early warning system. Real-time monitoring of the conditions in the areas adjacent to the power transmission and distribution lines should be conducted to implement dynamic management.

In addition, local climate information should be continuously collected and organized to ensure that the early warning system is always in real-time monitoring mode. In this way, once an abnormal situation occurs in the lines, an early warning can be issued in a timely manner, facilitating management personnel to take relevant measures after receiving the information and maintaining the stable operation of the power system.

4.1 Strengthen Patrol Inspections Along Power Transmission and Distribution Lines

• To ensure the safe operation of power transmission and distribution lines, it is necessary to strengthen inspection and maintenance of the lines. Specific inspection items include:

• Checking whether the distance between service drop lines, and the distance between the lines and buildings/ground (for crossing spans) are within the specified range, and whether the lines have aging or corrosion phenomena.

• Checking whether the supports of the lines are stable, and whether the supports have damage or rust.

• Inspecting the environment around the lines. For example, if there are blasting projects in the vicinity, checking whether the blasting projects have standardized blasting application procedures and whether the blasting safety measures are appropriate.

4.2 Strengthen Fire Prevention for Lines

• To ensure the safe operation of power transmission and distribution lines, fire prevention work should be strengthened in practical operations:

• Conducting comprehensive cleaning and investigation of potential fire hazards in the corridors of power transmission and distribution lines to reduce the probability of fire, and strengthening the maintenance and management of line operation.

• Enhancing communication and management of line information to dynamically and comprehensively grasp the operation status of power transmission and distribution lines, and improving the emergency response plan for mountain fire prevention in practice.

4.3 Strengthen Lightning Protection for Power Transmission and Distribution Lines

• Due to the inherent characteristics of power transmission and distribution lines, it is impossible to achieve complete lightning protection. Therefore, to maintain the safe operation of the lines, lightning protection measures should be taken:

• Erecting corresponding coupling ground wires.

• Reducing the grounding resistance of tower foundations, which is an effective method to improve the lightning resistance of the lines.

• Adopting arc suppression coils to prevent lightning strikes.