How to choose transformer bushing online monitoring system? Core indicators and configuration recommendations
Date: May 27, 2026 02:12:02
- Insulation or Insulation + Local DischargeInsulation monitoring for overall insulation condition assessment only, upgraded to integrated insulation + local discharge solution for early defect warning.
- Measuring range matching: Leakage currents and capacitance of casing at different voltage levels vary greatly, and the system range must match the parameters of the casing being monitored.
- environmental adaptation: Outdoor casing is significantly affected by temperature, humidity and dirt, and the system needs to be environmentally compensated.
1. Selection of core indicators
| norm | Scope of monitoring | Selection instructions |
|---|---|---|
| Leakage Current Measurement | 2mA~1000mA | Covers the complete current range from normal to abnormal |
| Capacitance Measurement | 100pF~50000pF | Capacities of casing of different voltage levels span a wide range and the ranges need to be matched. |
| Dielectric Loss Measurement | Measurement down to the thousandth level | The higher the dielectric loss resolution, the better the detection of early insulation degradation |
2. Configuration options
2.1 Basic insulation monitoring program
Only leakage current and dielectric loss are monitored to assess the overall insulation status of the bushing. Suitable for the basic monitoring needs of transformer bushings in a typical substation, and a relatively economical investment. The limitation is the inability to capture localized discharge signals - early insulation defects within the bushing may not be detected until the dielectric loss begins to change.
2.2 Integrated Insulation + Local Amplifier Program
Simultaneous monitoring of insulation parameters and local discharge signals, both to assess the overall insulation status and to capture local defects. It is suitable for high-voltage bushings of main transformers in important substations. Local discharge monitoring can detect localized defects before the overall insulation parameters change, providing an earlier warning window.
2.3 Integrated Monitoring Program for Tolerance Equipment
The monitoring of transformer bushings, current transformers, voltage transformers, surge arresters and other capacitive equipment in the same substation is unified into the same system platform. It realizes the integrated monitoring of the insulation status of capacitive equipment in the whole station, which is suitable for the comprehensive coverage of hub substations.
3. Frequently Asked Questions FAQ
3.1 Q. Are bushing monitoring and transformer local emission monitoring the same thing?
A: No. Transformer local discharge monitoring addresses the windings and insulation structure inside the transformer tank; bushing monitoring addresses the insulation status of the bushing itself. Both have different sensor types and installation locations, and monitor different equipment components.
3.2 Q. Is online monitoring required for all casing?
A: Not all bushings are required. Prioritization: 500kV/220kV main transformer HV bushings are given the highest priority, followed by bushings that have a long operating life or have had insulation abnormalities. Low voltage side bushings (35kV and below) can be deployed selectively.
3.3 Q. How many casing can a system monitor simultaneously?
A: Depends on the number of channels in the system. Normally a main transformer requires 3 monitoring channels for the three high voltage side bushings and 1 channel for the neutral bushing. The channel requirement is determined by the total number of monitored bushings when selecting the model.
Disclaimer: The content of this article is for technical exchanges and reference only, and does not constitute any form of procurement commitment or contract offer. Product technical parameters, configuration programs and prices are subject to the actual signed contracts and technical agreements. The technical data and cases involved in this article are from public information and engineering practice, if updated without notice.
Need advice on transformer bushing online monitoring selection? Welcome to contact Inotera for customized solutions and quotations. Service Hotline: 13959168359 (WeChat same number).
