What Should GIS Online Monitoring Focus On? SF6, Partial Discharge, and Circuit Breaker Status

The focus of GIS online monitoring is not on individual sensors, but rather on establishing continuous monitoring of the gas condition, insulation condition, circuit breaker status, surge arrester status, and expansion joint status of GIS equipment. Common areas of application include SF6 online monitoring, GIS circuit breaker online monitoring, GIS partial discharge online monitoring, surge arrester online monitoring, and GIS expansion joint online monitoring.

When selecting a GIS online monitoring system, the decision should be based on on-site equipment, control logic, communication methods, and maintenance procedures. Power equipment accessories and online monitoring devices typically do not operate in isolation but work in conjunction with transformers, switchgear, cables, backend platforms, alarm circuits, and operations and maintenance procedures. Clearly defining the application scenario is more beneficial for procurement and future maintenance than simply listing a series of model numbers.

1. Core Features and Target Audience

2. When selecting a model, first consider the on-site requirements

GIS equipment has a compact design, and the cost of maintenance during power outages is high. Once problems arise with internal insulation, gas conditions, or mechanical components, manual inspections often fail to detect them in a timely manner. Online monitoring converts these invisible conditions into data that can be recorded, analyzed for trends, and used to trigger alarms, making it more effective for detecting slowly developing defects.

3. Deployment and Operations Considerations

SF6 online monitoring focuses on the state of the gas; partial discharge (PD) online monitoring focuses on internal insulation defects and discharge activity; circuit breaker online monitoring focuses on operation and mechanism status; and surge arrester and expansion joint monitoring provides supplementary assessment from the perspective of protecting equipment and structural components. For new substations, interfaces can be reserved in advance; for retrofitted substations, it is recommended to first cover critical bays and equipment with a history of defects.

When requesting a quote or discussing technical matters, we recommend having the following information ready: equipment model numbers, on-site photos, installation locations, wiring configurations, backend integration requirements, and details about the existing system. For retrofit projects, you should also provide the nameplates of the original equipment, photos of the terminals, and a description of the control circuits; for new construction projects, you should plan the power supply, communications, panel space, measurement point names, and alarm levels simultaneously during the design phase.

4. Frequently Asked Questions

1. Does GIS online monitoring only monitor SF6?

No, it also includes areas such as partial discharge, circuit breakers, surge arresters, and expansion joints.

2. Can existing stations be retrofitted?

Planning can be carried out in batches based on installation space, power outage windows, and interface requirements.

3. Why should we integrate with a unified platform?

This facilitates a combined analysis of the status of equipment such as transformers, switchgear, and cables.

Note: The GIS status should be assessed comprehensively.

The internal status of GIS equipment is complex, and a single monitoring parameter often reflects only one aspect of its condition. The status of SF6, partial discharge signals, circuit breaker operations, surge arrester status, and expansion joint status should be analyzed in conjunction with the equipment’s location, operating conditions, and history of defects. For critical bays, it is recommended to establish long-term trend curves to monitor whether data consistently deviates from the normal range.

For retrofit projects, special attention must be paid to installation windows and interface requirements. Since opportunities for power outages affecting GIS equipment are limited, sensor installation, cable laying, panel connections, and backend debugging should all be planned in advance. The more thorough the preparatory work completed before the power outage window, the lower the risk during on-site implementation.

7. Summary

The value of a GIS online monitoring system lies not merely in its initial installation, but in making it easier to detect, record, and address equipment status issues. Clearly defining the target equipment, interfaces, control logic, and operations and maintenance processes during the selection phase will ensure more stable operation in the long run. If you have any questions regarding model, size, interfaces, or technical details, refer to the project technical agreement and the manufacturer’s latest documentation.

5. When conducting comprehensive online monitoring using GIS, it is important to analyze each object individually

GIS equipment has a compact structure, and its live parts are enclosed, making it difficult to directly observe the internal condition during routine inspections; therefore, online monitoring should focus on key components. SF6-related monitoring focuses on the condition of the insulation and arc-quenching medium; partial discharge (PD) monitoring focuses on internal insulation defects or signs of abnormal discharge; and circuit breaker condition monitoring focuses on mechanism operation, energy storage, and status changes during operation. Combining these monitoring targets into a single system does not imply that all data is interpreted in the same way; different monitoring parameters require corresponding alarm logic and verification methods.

During the planning phase, it is recommended to first identify the number of GIS bays, monitoring targets, on-site communication conditions, backend platform interfaces, and operational and maintenance practices. For critical bays, priority should be given to historical defects, load importance, years in service, and the difficulty of maintenance. Once the monitoring system is fully implemented, alarms should be categorized into trend-based, sudden-change, and interlock-based alerts for processing. This approach helps prevent overinterpretation of isolated data changes and ensures that appropriate priorities are assigned when multiple anomalies occur simultaneously.

6. Practical Value in Operations and Maintenance Management

The value of GIS online monitoring lies in the early detection of status changes and in providing evidence to support maintenance scheduling. Operations and maintenance personnel can use historical trend curves to determine whether anomalies are continuing to develop, compare similar intervals to identify deviations in individual equipment, and correlate data from multiple sources to determine whether problems are concentrated in a specific area. For critical substations, comprehensive online monitoring also helps reduce blind spots in manual inspections, shifting the focus from “routine periodic checks” to “problem-driven verification.” While such systems do not replace on-site testing, they can enhance the precision of testing and maintenance schedules.