Online Monitoring System for Circuit Breaker Mechanical Characteristics

Integrates electrical and mechanical characteristic monitoring;

Expandable for vibration, moisture, and hydraulic characteristic monitoring;

Full digital sampling, networking, and realization of comprehensive monitoring in smart substations!

Product Overview

At present, the maintenance of electrical equipment in substations in our country mainly relies on regular preventive tests. The results of these tests are used to determine the operating condition of the equipment and whether it can continue to operate. Over the long term, the adherence to preventive testing has played a significant role in ensuring the safe operation of our power system. However, with the increasing capacity, higher voltage levels, and more complex structure of the power system, as well as the advancement of modern science, the requirements for the safety and reliability of the power system have also become more stringent. The traditional testing and diagnostic methods are becoming increasingly inadequate to meet these needs.

For the above reasons, relying solely on traditional preventive testing and regular maintenance can no longer meet the rapidly developing requirements of the power system. In order to ensure the safe operation of the power system and minimize the accident rate, it is urgent to implement condition-based maintenance of electrical equipment. Condition-based maintenance of electrical equipment involves identifying equipment abnormalities and predicting operational trends based on equipment status information provided by advanced condition monitoring and diagnostic technologies, and performing maintenance before failures occur. In recent years, it has been found that relying on online monitoring and diagnostic technologies for equipment to implement condition-based maintenance can meet the requirements of the power system.

Technical Principles

1. Monitoring of Mechanical Life of High-Voltage Circuit Breakers

1.1 Monitoring and Judgement Method of Opening (Closing) Coil Current

The electromagnet is one of the important components of the operating mechanism of a high-voltage circuit breaker. High-voltage circuit breakers generally use the electromagnet as the first-level control component. When current flows through the coil, flux is generated within the electromagnet, and the core is attracted by the electromagnetic force, causing the circuit breaker to open or close. The current in the coil contains a lot of information, reflecting the working conditions of the electromagnet itself as well as the controlled latch or valve and the interlocking contacts during the operating process.

1.2 Monitoring of Moving Contact Travel

The travel-time characteristic of a high-voltage circuit breaker is an important parameter for characterizing the mechanical properties of the breaker and is also the basis for calculating the opening and closing speeds of the high-voltage circuit breaker. The opening and closing speeds of the high-voltage circuit breaker, especially the speed of the moving contact before closing and after opening, have a crucial impact on the breaker's interrupting performance. The measurement of the moving contact speed of the high-voltage circuit breaker is mainly achieved by measuring the travel-time relationship of the moving contact and then calculating the speed and other parameters of the moving contact.

2．Monitoring of Vibration Signals

For high-voltage circuit breakers, vibration signals during the opening and closing operations contain a wealth of mechanical status information, and even subtle changes in the mechanical system structure can be detected from these vibration signals. Therefore, using external vibration signals as characteristic signals can be employed to monitor the mechanical condition of high-voltage circuit breakers. The specific approach is to collect vibration signals at appropriate locations on the circuit breaker and use the processed signals as the basis for diagnosis.

Based on the principle of similarity, for the same high-voltage circuit breaker, the external vibration signals are stable within a certain range during repeated operations in the same state, that is, the collected vibration signal waveforms are similar. By comparing the currently collected vibration signals with the known state vibration signals and analyzing their degree of similarity, corresponding judgments can be made.

3．Monitoring of Electrical Life of High-Voltage Circuit Breakers

The monitoring of the electrical life of high-voltage circuit breakers mainly focuses on two representative parameters: the monitoring of the breaking current of the circuit breaker and the monitoring of the number of breaking operations.

For any type of circuit breaker, its rated breaking current and the corresponding allowed number of breaking operations can be found in the product specifications. First, we define the allowable wear of the contacts for a brand-new circuit breaker as 100%, that is, the relative electrical life is 1. The relative wear for each rated breaking current operation is 1/N, and the relative electrical wear for a single breaking operation (defined as Qm) for different circuit breakers is 1/M. In this way, the relative electrical wear for any breaking current can be calculated, as well as the relative electrical life of the circuit breaker.

Product Advantages

1．A multi-parameter, multi-functional open integrated monitoring system

The system adopts a modular design to achieve online monitoring of multiple parameters of substation electrical equipment on the same monitoring platform. The system platform has good openness and expandability. In addition to completing the current multi-variable and multi-functional monitoring, it can also flexibly expand functional modules according to needs to achieve online monitoring of new characteristic quantities. It is also easy to integrate third-party online monitoring devices to supplement functions.

2．Flexible system configuration and easy networking

Since each subsystem is relatively functionally independent and structurally complete, the system can be flexibly configured according to the actual monitored characteristic quantities and the user's on-site environment. For example, when there are fewer monitored devices, the industrial computer, server, and client software can be implemented on the same computer. At the same time, the system's communication methods are basically compatible with the currently popular methods, including telephone dial-up, local area network, optical fiber, Intranet, and Internet. This reduces the limitations of the system networking on the on-site network conditions of the substation.

3．Reliable system operation, good electromagnetic compatibility, and strong on-site anti-interference capability

The system employs digital filtering, adaptive signal processing, multiple electromagnetic shielding, and other hardware and software technologies and processes, enabling it to operate normally in the strong electromagnetic environment of a substation. The system has passed the pulse group interference test, surge immunity test, fast transient immunity test, electrostatic discharge (ESD) immunity test, and radiated immunity test.

4．  Good testability and maintainability of the system

The system adopts a standardized modular design with good interchangeability and independence of components. The system is equipped with self-diagnosis functions, which are convenient for users to use. Remote maintenance reduces the workload of users in maintaining the online monitoring system itself.

5．The monitored data is stable, reliable, and highly accurate, with good consistency and comparability to offline measurement data.

The system has undergone several years of on-site trial operation in substations of various voltage levels and has been continuously improved. Currently, all operating products provide accurate and stable monitoring data, which is comparable to the offline measurement data of the using departments and shows good consistency, earning the trust of users.

6．  Comprehensive equipment protection measures

The product has adopted a variety of protective measures to ensure that it has excellent insulation performance as well as moisture-proof, mold-proof, salt fog-proof, and corrosion-resistant properties.

Product Advantages

1．Installation Steps

（1）Before installation, engineering and technical personnel will conduct on-site surveys to develop a detailed construction plan and personnel arrangement, and work with the client's staff to prepare for the construction.

（2）A detailed construction plan should be developed and submitted to the client for approval before installation. The plan should include detailed information such as the installation locations of sensors and cabinets, power outage times, cable routing, specific construction times and locations, and tasks that require the client's cooperation.

（3）All sensors, monitoring devices, and any piping or valves that may cause leakage (such as oil chromatography and moisture monitoring for main transformers) should be strictly tested before installation.

（4）When performing installation and commissioning, relevant safety regulations must be strictly followed, and work should not be carried out outside the designated area. No damage should be caused to the substation. After cable laying, the original condition should be restored, and a thorough cleaning should be conducted after installation.

（5）The installation and layout of all sensors, monitoring devices, shielded cables, and industrial computers (cabinets) should be neat and should not damage the overall aesthetics of the substation. Warning signs should be hung in places where accidental contact or incorrect wiring may occur.

2. Installation Schematic

（1）The installation schematic for the circuit breaker monitoring unit is as follows.                           （2）The installation schematic for the mechanical travel sensor is as follows.

（3）Installation Schematic for Closing/Opening/Charging Motor Coil Waveform Sensor                    （4）Installation Schematic for Vibration Sensor 

Technical Parameters

Service Assurance

l  Provide remote telephone or video guidance. On-site installation, commissioning, and demonstration training operations are available for a fee

l  Provide detailed Chinese instruction manuals and user guides.

l  One-year free warranty, lifetime spare parts support, and maintenance.

l  24/7 hotline available 365 days a year to answer user inquiries.