What are partial discharges and why do they matter?
Partial discharges are localized electrical discharges that indicate a weakness in an insulation system. They can occur in medium- and high-voltage cables, transformers, switchgear, switching devices, and other insulated electrical equipment.
Partial discharge activity may be present even when the equipment continues to operate normally and shows no visible signs of a fault. If the underlying insulation defect is not addressed, the activity can continue to degrade the insulation and eventually contribute to a flashover, short circuit, equipment failure, or power outage.
Partial discharges are associated with a significant share of faults in medium- and high-voltage systems. Detecting them at an early stage therefore supports electrical network condition monitoring, preventive maintenance, operational reliability, and electrical safety.
A partial discharge measurement provides condition data that can be used to assess possible insulation defects and plan corrective action before more extensive damage occurs.
Partial discharge measurements are performed without a shutdown
Insta performs partial discharge measurements while the electrical network remains in normal operation. The measurement does not require a planned power outage or production shutdown. During the measurement, data is collected from cables, transformers, switchgear or switching devices to identify possible partial discharge activity that may indicate developing insulation defects.
For the customer, the measurement is a simple and minimally disruptive procedure that can typically be carried out within a few hours, including setup and completion, as part of normal network operation. After the analysis, the customer receives a report that includes the observed partial discharge activity, an assessment of insulation condition and recommendations to support maintenance planning.
Ask more about the service:
Contact usWho should consider partial discharge measurements?
PD measurements are intended for organizations where the reliability of the electrical network is critical to business continuity, production, or facility operations. They are particularly relevant in environments where power interruptions can result in significant costs, production losses, or operational risks. The service also supports electrical operations management by providing up-to-date condition data for maintenance planning and investment decisions.
Typical applications include:
industrial facilities and production plants, including forest industry and OEM sites
energy producers, utilities, and electricity distribution companies
data centers
hospitals and other critical infrastructure facilities
Shopping centers, logistics centers and other owners of private medium- and high-voltage distribution networks
Partial discharge measurements can also be used as part of the commissioning and acceptance testing of new medium- and high-voltage systems.
From PD measurement to corrective action with one partner
Insta can provide both the partial discharge measurement and the corrective work identified based on the results. Depending on the findings and the equipment involved, further action may include:
replacement of cable terminations or cable joints
cable replacement
transformer station repairs
cleaning of electrical equipment
equipment renewal or modernization
other electrical distribution maintenance and life-cycle services
Corrective measures are planned according to the condition, criticality, and operating environment of the equipment. The customer may also use the measurement report when arranging corrective work through another service provider.
Partial discharge measurements can be included in electrical distribution maintenance agreements. Recurring measurements make it possible to monitor changes in equipment condition and plan maintenance as part of a preventive maintenance program.
Insta as a life-cycle partner for electrical distribution
Insta has extensive experience in the construction, maintenance and condition monitoring of medium- and high-voltage electrical networks. As a manufacturer-independent service provider, we work with equipment from multiple manufacturers and provide a comprehensive view of the condition of the electrical network.
Partial discharge measurements complement Insta’s electrical distribution services, including expert services, maintenance, lifecycle services and electrical operations management. Through a single partner, customers gain access to network engineering, condition monitoring, operational support and the corrective actions needed throughout the lifecycle of electrical distribution assets, from maintenance to equipment renewal and modernization.
Power distribution consultingLifecycle services of electrical distribution equipment
