Overall Design of a 10kV High-Voltage Switchgear Wireless Temperature Measurement System

1. Overall Design

This article selects the KYN type switchgear as the research object, with K, Y, and N representing armored metal-enclosed switchgear, movable structure, and indoor installation, respectively. In accordance with the safety operation requirements of 10kV high-voltage switchgear, the overall design of the 10kV high-voltage switchgear must consider factors such as volume, insulation performance, cost, and reliability. The system design analysis primarily consists of three parts: the high-voltage transmitter, the low-voltage receiver, and the supervisory computer data processing and control. This design takes into account the six plum blossom terminals of the KYN type switchgear and provides a 470MHz wireless data transmission channel. With the CT transformer selected as the high-voltage side power source and the ATE400 temperature sensor measuring the terminal temperature, the system can accurately reflect the changes in terminal temperature.

2. Selection of Temperature Sensors

Temperature sensors commonly used in general industrial settings include thermocouple temperature sensors, resistance temperature detectors (RTDs), thermistors, and integrated temperature sensors. By integrating multiple sensors, it's evident that each sensor has a distinct temperature measurement range. This clear temperature range value helps understand the sensor's adaptability to changes in temperature environments. Considering design costs and complexity, most 10kV high-voltage switchgear wireless temperature measurement systems opt for the ATE400 temperature sensor. The reason is primarily that the ATE400 temperature sensor offers a reasonable price point, along with high-precision measurement, simple temperature measurement pathways, and ease of use.

3. Selection of high and low voltage side signal transmission methods

The choice of wireless signal transmission method plays a significant role in the design quality of the 10kV high-voltage switchgear wireless temperature measurement system. Wireless signal transmission methods include Bluetooth technology, infrared technology, and others. However, due to the varying degrees of interference resistance and power consumption among different technologies, the 10kV high-voltage switchgear wireless temperature measurement system primarily opts for Bluetooth technology for wireless signal transmission.

4. Selection of High-Voltage Supply Method

The high-voltage side circuits in the power supply room must meet requirements for uninterrupted power supply, strong anti-interference capability, and high stability output. Current power supply methods include laser, solar, CT transformer power supply, and battery power supply. However, the 10kV high-voltage switchgear wireless temperature measurement system primarily utilizes CT transformer power supply due to its ability to better meet the diverse needs of the high-voltage side circuits, along with its advantages of structural safety, mature application, and excellent operating environment.

Section II: Principle of the 10kV High-Voltage Switchgear Wireless Temperature Sensing Sensor

1. Wireless Temperature Measurement Principle

Integrating various temperature sensing elements for temperature measurement is the principle of wireless temperature measurement. These temperature sensing elements include thermistors, infrared temperature sensors, semiconductor sensors, acoustic surface temperature sensors, and passive wireless temperature sensors.

2. Thermistor Temperature Sensor

In response to varying temperatures, its resistance value also undergoes different degrees of change, which is the principle of thermistor temperature sensors. Conversely, the size of the resistance can be used to determine the temperature's high or low. Its advantages are evident due to its high sensitivity, while its disadvantages include the degradation of the linear relationship between the thermistor value and temperature, leading to component aging, shortened lifespan of the thermistor temperature sensor, and reduced accuracy and stability of temperature measurement over extended use.

Infrared Temperature Sensor

The blackbody radiation law is the principle behind the application of infrared temperature sensors, which states that any object above 0P will unconsciously emit infrared radiation. Its characteristic is the use of non-contact measurement, which means that the measuring probe and the object being measured do not need to be obstructed and no insulation treatment is required. However, infrared temperature sensors are very susceptible to temperature and humidity...

Due to factors such as temperature and radiation, there has been a deviation in the temperature measurement accuracy.

4. Semiconductor Sensor

PN, as a temperature sensing element, operates on the principle that its resistance changes with temperature variations. By enhancing a constant current and combining it with the current magnitude during operation, the temperature of the high-voltage switchgear can be determined. Although this method offers high accuracy in temperature measurement, its overall sensitivity is not as high as thermistors due to a longer response time. However, semiconductor sensors are less prone to aging and have a longer service life, thus offering higher reliability.

5. Acoustic Surface Temperature Sensor

The acoustic surface wave temperature sensor employs a unique measurement method, which is a passive measurement. It can utilize wireless transmission to measure the specific temperature of high-voltage switchgear. Its overall advantage lies in its compact size and the fact that it does not require a power source. However, the transmission distance is limited, and there must be no obstacles during the entire transmission process, as this can easily cause displacement and vibration, leading to phase changes on the acoustic surface, which may affect the accuracy of the temperature measurement.

6. Passive Wireless Temperature Sensor

Energy collection methods are employed to meet the power demands of passive wireless temperature sensors, thereby fully eliminating the need for traditional batteries and CT power extraction. The entire passive wireless temperature sensor boasts high safety and reliability. The energy collection technology is pollution-free, with the added benefits of being recyclable and low-energy consuming. As a result, the development of future wireless temperature measurement systems will largely be based on microelectronics and low-power consumption technologies, presenting various approaches akin to the passive wireless temperature sensors.

III. Technical Features of the Wireless Temperature Measurement System

1. Security

The standalone wireless temperature measurement system with independent potential insulation installation is designed to effectively mitigate the adverse effects of creeping electricity over a wide range, while also significantly enhancing the safety performance of electrical equipment. Consequently, the technology of the entire wireless temperature measurement system presents a high level of safety.

2. Accuracy

The majority of components used in wireless temperature sensing systems are high-precision digital sensors, which undoubtedly confirm that the majority of temperature measurement methods are contact-based. The position of the entire sensor is extremely close to the heat source, enabling the rapid determination of temperature changes at specific points, and demonstrating the overall measurement accuracy of the wireless temperature sensing system.

3. Flexibility

Due to the compact size of the wireless temperature measurement device, the installation process is extremely convenient, and the network setup is highly flexible, supporting both wireless and wired network connections. The small size of the device also facilitates the installation of multiple monitoring points, enabling the collection of measurement data.

4. Usability

The entire operation platform of the wireless temperature measurement system is mainly designed with modularization, making it more convenient to link to the network and thus achieve an automated control system. Overall, its usability is also more convenient.

5. Low power consumption

The application of low-power design principles to wireless temperature measurement allows for accurate temperature readings while extending the lifespan of wireless temperature sensors.

Section 4: Application of Wireless Temperature Measurement Technology for 10kV High-Voltage Switchgear

Currently, numerous enterprises, research institutions, and departments in our country have developed various types of 10kV high-voltage switchgear wireless online temperature detection and measurement systems. For instance, one company has already developed a special device, which, from a normal perspective, is a non-contact temperature monitoring system. Its primary function is to continuously monitor the temperature of a specific location within the distribution switchgear, which is a critical part of the entire 10kV high-voltage switchgear. Monitoring this location aims to obtain a high-accuracy operational status and temperature, while the non-contact temperature monitoring system also monitors the circuit breaker's operational status. The non-contact temperature monitoring system utilizes quartz crystal surface acoustic wave components. It is well-known that these components are applied in 10kV high-voltage switchgear wireless temperature measurement technology as temperature-sensitive elements, directly粘贴 at the point to be measured. The 10kV high-voltage switchgear equipped with temperature-sensitive elements forms an oscillating circuit that outputs frequency signals related to temperature. The application of wireless temperature measurement technology in the 10kV high-voltage switchgear fully satisfies system requirements and leverages its digital characteristics, further suppressing the interference of strong electric fields to achieve overheat alarms. Additionally, the monitoring equipment can utilize microcomputer networking to achieve centralized monitoring.

The advantages of the wireless temperature measurement system applied in 10kV high-voltage switchgear are quite evident, including reliable performance, simple structure, compact size, easy installation, and operation. Therefore, most 10kV high-voltage switchgears are equipped with wireless temperature measurement systems for corresponding temperature monitoring. Moreover, the price of the entire wireless temperature measurement system is not high, falling within the acceptable price range for consumers. The small and compact design of the wireless temperature measurement module facilitates easy adaptation to switchgear, allowing for quick installation even if the original cabinet structure remains unchanged. With just the corresponding switchgear components and the creation of appropriate installation holes, a rapid installation can be achieved. The installation process does not affect the performance of the original switchgear's wireless temperature measurement system, particularly in terms of insulation properties, which remain excellent throughout the installation. The safe production of smart grids is a massive and complex engineering project, and through continuous development of the engineering system, it is clear that the system engineering is a prerequisite for reform and innovation in power companies and society as a whole, continually propelling the development of China's smart grid. As early as 2006, the state issued several important documents on the safe use of system power equipment, clearly recognizing that the national priority for development and implementation is the security of smart grid. Currently, China is in a period of economic growth, and the power supply volume of the national grid cannot meet the daily lives and production needs of the society. Therefore, the state needs to increase the power supply volume of the grid, but this will lead to potential hazards in electrical equipment, especially for the 10kV high-voltage switchgear at the end of the smart grid. Thus, ensuring the safety of high-voltage switchgears is crucial to further enhance the grid's temperature monitoring effectiveness.

Ankorri Online Temperature Monitoring System Solution

1. Overview

The electrical contact online temperature measuring device is suitable for temperature monitoring of equipment such as cable joints, circuit breaker contacts, knife switches, high-voltage cable mid-sections, dry transformers, and low-voltage high-current devices within high and low-voltage switchgear cabinets. It prevents potential safety hazards caused by overheating due to factors like oxidation, loosening, and dust, which can lead to excessive contact resistance. This device enhances equipment safety, provides timely, continuous, and accurate feedback on equipment operation, and reduces the incidence of equipment accidents.

The Acrel-2000T Wireless Temperature Monitoring System communicates directly with equipment at the bay level via RS485 bus or Ethernet. The system design adheres to international standards such as Modbus-RTU and Modbus-TCP, significantly enhancing its security, reliability, and openness. The system features remote signaling, remote measurement, remote control, remote adjustment, remote setup, event alarms, curve plotting, bar graphs, reports, and user management capabilities. It can monitor the operational status of wireless temperature measurement system devices, achieve rapid alarm response, and prevent severe failures.

2. Application Sites

Temperature monitoring suitable for power equipment in various industrial and mining enterprises such as ubiquitous power Internet of Things, steel mills, chemical plants, cement factories, data centers, airports, power plants, coal mines, and substation transformer stations.

3. System Architecture

Temperature Online Monitoring System Schematic

4. System Features

The Acrel-2000T temperature monitoring system is installed in the duty monitoring room, enabling remote monitoring of the operating temperatures of all switchgear within the system. The system boasts the following main features:

1) Temperature Display: Show the real-time values of each temperature sensing point within the power distribution system, and can also be remotely accessed via computer WEB or mobile APP.

2) Temperature Trend Curves: View the temperature trend curves for each temperature sensing point.

3) Operation Report: Query and print temperature data at various temperature measurement points.

4) Real-time Alerts: The system can issue alerts for abnormal temperatures at various temperature sensing points. It features real-time voice alarm capabilities, enabling voice alerts for all events. Alerts can be delivered through pop-ups, voice alarms, and also via SMS or APP push notifications to promptly remind on-duty personnel.

5) Historical Event Inquiry: Capable of storing and managing records of events such as temperature limits, facilitating users in tracing historical system events and alarms, and conducting inquiries, statistics, and accident analysis.

5. System Hardware Configuration

The online temperature monitoring system is primarily composed of temperature sensors and temperature collection/display units at the equipment layer, edge computing gateways at the communication layer, and the temperature measurement system host at the station control layer, enabling real-time monitoring of temperatures at critical electrical components of the power distribution and transformation system.

Six, Conclusion

In-depth analysis of the wireless temperature measurement technology for 10kV high-voltage switchgear, combining the actual features and development status of the technology, aims to ensure the safe and stable operation of the smart grid, and to promote the continuous advancement of the wireless temperature measurement technology for 10kV high-voltage switchgear.