Cutting Energy Losses via Continuous Partial Discharge Monitoring

In modern energy distribution, one of the most significant challenges is minimizing energy losses. This article explores the types of losses in electrical distribution systems, highlights the importance of monitoring partial discharges, and examines the role of measurement vehicles in traditional maintenance practices.

What are the basic types of energy losses?

Energy losses in distribution networks can be categorized into three primary types:

• Joule Losses: They occur due to the resistance of conductors, leading to heat dissipation. These losses can be reduced by optimizing the energy flow within the grid, such as reconfiguring distribution lines to minimize resistance-related energy dissipation.
• Losses from Corona Discharges: Corona discharges, a type of partial discharge, occur in non-uniform electric fields. Factors like conductor curvature, surface contaminants, or ice buildup contribute to their occurrence. These discharges lead to charge leakage, causing energy losses that, under certain conditions, can reach 150% of typical loss levels.
• Leakage Losses, which arise from current flow along contaminated insulators, such as those covered in dust or ice. These currents are accompanied by partial discharges, which degrade insulation and increase losses by creating conductive paths along the insulator surface.

How can monitoring for partial discharges deal with energy losses?

Installing partial discharge sensors near power equipment, such as substations or transformers, enables continuous monitoring of these phenomena. This approach provides several key benefits:

• Crisis Prevention: Partial discharges indicate insulation degradation, allowing timely maintenance and reducing the risk of equipment failure.
• Loss Optimization: Identifying areas with high discharge activity enables targeted upgrades, such as using semi-insulated conductors that mitigate corona losses.
• Efficient Maintenance Planning: Real-time insulation monitoring can replace traditional inspection methods, such as periodic testing with cable testing vehicles.

Traditional inspection with cable testing vehicles: is it any good?

Before the advent of continuous monitoring systems, maintenance teams relied heavily on cable testing vehicles to assess the insulation state of electrical equipment. These vehicles are typically equipped with high-voltage measurement devices and serve as mobile diagnostic labs. In practice, the operation of these vehicles involves significant logistical challenges.

A vehicle can perform an average of five inspections per day, often covering large geographic areas. For instance, E.ON operates 19,623 substations in the Czech Republic, requiring approximately 4,000 annual inspections, or about 20 inspections per day across all regions.

The vehicles must travel round trips to various substations, increasing fuel consumption and operational costs. These substations are often located in both urban and rural areas, with rural locations requiring longer travel distances. This impacts the efficiency of traditional maintenance and highlights the benefits of adopting continuous monitoring systems.

An average travel distance for one inspection of stations in South Bohemian region, with starting point in České Budějovice, is 36,8 kilometers. Notice that throughout whole journey, the vehicles’ onboard equipment is powered by the engine, further contributing to energy use.

Weather: another factor significantly impacting energy losses

Research indicates that weather significantly influences the occurrence of partial discharges. While average loss values are often based on meteorological data, local conditions — such as frequent fog, frost in mountainous regions, or industrial dust near factories — can lead to higher actual losses.

The following tables shows total technical losses in Moravian part of the transmission system, based on current weather:

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What are the economic advantages of partial discharge monitoring?

Implementing partial discharge monitoring systems offers substantial financial and operational benefits:

1. Reduced Maintenance Costs: Automated monitoring systems reduce the need for labor-intensive inspections with measurement vehicles.
2. Enhanced Operational Safety: Early detection of issues minimizes the risk of failures, which can lead to costly repairs and safety hazards like fires.
3. Informed Investment Decisions: Loss data can guide the adoption of advanced technologies, such as insulated conductors in high-loss areas.

Case Study: Energy Loss Analysis in the Czech Republic

Energy provider E.ON operates over 19,600 substations in the Czech Republic and conducts approximately 4,000 inspections annually using testing vehicles. Each vehicle performs five inspections daily, covering equipment distributed across large regions. The vehicles must travel round trips to each substation, with average travel distances varying based on regional factors. Additionally, onboard equipment relies on the engine for power, increasing operational costs.

Similarly, ČEZ Distribuce reported average losses of 41 kWh/km on its high-voltage lines in 2019. Of these, approximately 20% were attributed to corona discharges. By implementing real-time monitoring and upgrading infrastructure, such losses can be significantly reduced.

Conclusion

The adoption of continuous partial discharge monitoring represents a major step forward in improving the efficiency and safety of energy systems. This technology not only minimizes losses but also enhances maintenance planning and investment decisions. As the demand for sustainable energy grows, implementing such innovations will be essential to meet future challenges.

Do you wish to minimize your energy losses?