In modern industrial systems, alumina, as a key inorganic non-metallic material, is widely used in metallurgy, electronics, ceramics, environmental protection, and other fields due to its excellent physicochemical properties. It is an important foundational material driving my country's industrial upgrading. From daily necessities to industrial equipment, alumina applications are ubiquitous. Its non-toxic, odorless, and chemically stable characteristics make it an environmentally friendly material, allowing for further expansion into environmental protection, biotechnology, and other fields with high material safety requirements.

The stable operation of alumina production plants relies on reliable power system support. As the core link in power distribution, the safety and stability of the switchgear in 10kV substations directly determines the continuity of alumina production. Acrel's integrated intelligent control, wireless temperature measurement, and partial discharge monitoring device can achieve coverage of switchgear environmental monitoring, switch status control, real-time monitoring of electrical contact temperature, and partial discharge early warning, effectively avoiding safety hazards such as insulation aging and contact overheating, providing strong technical support for the power supply guarantee of alumina production.

 

Project Overview

Located in Hepu County, Beihai City, Guangxi Province, this project is a benchmark project for the circular economy in Beihai's aluminum industry. The first phase is designed to produce 4.8 million tons of alumina annually. Working in conjunction with the Guangxi Investment Group Beihai Green Ecological Aluminum Project, it will create an industrial scale of 4 million tons per year, with an estimated annual output value of 70 billion yuan, laying a solid foundation for the improvement of the regional ecological aluminum industry chain. Leveraging abundant overseas bauxite resources and convenient local port transportation advantages, the project responds to Guangxi's aluminum industry development strategy of "both ends domestically, and the middle abroad," striving to create a green and low-carbon industry chain integrating resource import, production and processing, and recycling. Upon completion, the project will closely link with downstream industries such as electrolytic aluminum and photovoltaic glass, significantly improving the local conversion rate of aluminum resources and promoting the development of the regional aluminum industry towards specialization, greening, and intensification.

The project officially commenced construction in June 2025. To ensure the safe and stable operation of the plant's power system, its 10KV medium-voltage substation specifically selected Acrel's integrated intelligent control, wireless temperature measurement, and partial discharge monitoring products. This enables real-time monitoring and control of the switch cabinet environment, electrical contact temperature, switch status, and partial discharge conditions, thereby mitigating potential power safety hazards at the source and providing a reliable power guarantee for the continuous and stable production of alumina.

Product requirements, configuration options, and product introduction

2.1 Product Requirements

Based on the actual operational needs of the 10kV substation in this project, three core products are required: intelligent control, wireless temperature measurement, and partial discharge monitoring, to achieve monitoring and control of the switchgear. Specific requirements are as follows:

The intelligent control device must have monitoring and control functions, and be able to monitor the system's operating electrical parameters (voltage, current, power, etc.) and physical quantities in real time, including dynamic simulation display of switch status, high-voltage live display and interlocking, voltage detection and phase verification functions, wireless temperature measurement data display, switch cabinet partial discharge data monitoring, and environmental temperature and humidity monitoring. At the same time, it must integrate practical functions such as forced heating, forced lighting, human body induction, voice alarm prompts, remote/local switching, opening and closing switches, and energy storage switches to achieve integrated monitoring and control.

The partial discharge monitoring device for switchgear must meet the following detailed technical requirements:

1. Operating power supply: DC 12-36V, compatible with the existing power supply system of the substation;

2. Measurement content: It can simultaneously monitor ultrasonic waves (AE), ground electromagnetic waves (TEV), ultra-high frequency (UHF), environmental noise, temperature, and humidity, realizing multi-dimensional monitoring of partial discharge;

3. Ultrasonic (AE): Measurement range 0dBμV~60dBμV, resonant frequency 40kHz±1kHz, ensuring partial discharge acoustic signal capture;

4. Ground Electric Wave (TEV): Measurement range 0dBmV~60dBmV, measurement signal bandwidth 3MHz~100MHz, compatible with the frequency band of partial discharge signals in switchgear;

5. Ultra-high frequency (UHF): Measurement range -70dBm~10dBm, measurement frequency band 300MHz~1500MHz, equivalent height ≥10mm, improving the sensitivity of partial discharge signal monitoring;

6. Environmental noise measurement range: 30dB~130dB, which can eliminate environmental interference and identify partial discharge signals;

7. Ambient temperature measurement range: -40℃~85℃, ambient humidity measurement range: 0~100%RH, suitable for complex industrial environments;

8. Communication Protocol: Supports MODBUS-RTU protocol, enabling seamless integration with intelligent control devices;

9. Installation method: Magnetic installation is adopted, which does not require damage to the switch cabinet structure and facilitates construction and subsequent maintenance.

Wireless temperature measurement devices must meet the following detailed technical requirements:

1. Working power supply: It adopts the CT induction power supply method, with an induction current ≥5A, which eliminates the need for additional power supply lines and is suitable for the on-site working conditions of the switchgear.

2. Sampling frequency: 15 seconds/time, which can capture the temperature changes of electrical contacts in real time and avoid missed temperature anomalies;

3. Wireless frequency: 470MHz, ensuring stable temperature data transmission and strong anti-interference capability;

4. Communication distance: ≥150m in open environments, covering the layout area of substation switchgear;

5. Temperature measurement range: -50℃~125℃, suitable for full-range monitoring of electrical contacts during normal operation and abnormal temperature rise;

6. Temperature measurement accuracy: ±1℃, ensuring reliable temperature data and providing accurate basis for abnormal early warning;

7. Installation method: It is fixed with alloy plates, which can be used to install it firmly and can be adapted to various electrical contacts in switch cabinets (busbar joints, circuit breaker contacts, etc.).

Based on the above technical requirements, this project selected three core products from Acrel. The specific product parameters and installation methods are shown in the table below:

 

2.2 Configuration Scheme

This project covers the 10KV high-voltage switchgear in the plant area, adhering to the principle of "one switchgear, one monitoring system" to achieve comprehensive monitoring. The specific configuration plan is as follows:

 

2.3 Product Introduction

The Acrel ASD500 intelligent control device, APD300-L partial discharge monitoring device, and ATE400 wireless temperature sensor selected for this project work together seamlessly to form a comprehensive integrated monitoring system for the switchgear, effectively achieving closed-loop management of "monitoring-early warning-control" . The following is a detailed introduction to the three core products:

(The image above is a network diagram of the ASD500 intelligent control device, ATE400 wireless temperature sensor, and APD300-L partial discharge monitoring device, clearly showing the data transmission path and collaborative working logic of the three.)

2.3.1 Intelligent Control Device ASD500

The ASD500 switchgear integrated monitoring and control device is the core terminal of this integrated monitoring system. It is suitable for 3~35kV indoor switchgear and can be widely adapted to various switchgear types such as medium-voltage switchgear, handcart switchgear, fixed switchgear, and ring main unit. It integrates monitoring, display, control, and alarm functions to fully meet the project's comprehensive management and control needs for switchgear.

The core functions of this device are as follows:

1. Basic monitoring and control functions: It has a primary circuit simulation diagram and dynamic indication of switch status, high-voltage live display and interlocking, voltage detection and phase verification functions, which can intuitively present the operating status of the switchgear; it integrates functions such as opening and closing circuit integrity indication, opening and closing circuit voltage measurement, and pre-opening and pre-closing flashing indication, which facilitates on-site operation and inspection by staff; it supports human body induction automatic lighting to improve the convenience of on-site operation, and is also equipped with voice prompt function, which can provide voice alarm for high-voltage liveness, abnormal operation and other situations to ensure the personal safety of staff.

2. Temperature and Humidity Monitoring and Control Function: Utilizing digital temperature and humidity control, the system measures and clearly displays the ambient temperature and humidity data on an LCD screen in real time. Built-in heating and ventilation control contacts allow users to set upper and lower limits according to site conditions. The specific control logic is as follows: Heating automatically starts when the relative humidity is ≥85%; heating stops when the relative humidity is ≤77%; the fan starts to dissipate heat when the ambient temperature is ≥40℃; ventilation stops when the temperature is ≤35℃; heating anti-freeze is activated when the ambient temperature is ≤5℃; and heating stops when the ambient temperature is ≥13℃, effectively preventing damage to the equipment caused by condensation, overheating, or icing inside the cabinet.

3. Wireless Temperature Measurement Data Integration and Display Function: The device seamlessly connects with the ATE400 wireless temperature sensor via a wireless temperature receiver, receiving real-time temperature data from each electrical contact and displaying it synchronously on an LCD screen. This allows staff to intuitively monitor temperature changes at the contacts. When the temperature exceeds the preset high-temperature threshold, the device automatically generates an alarm record and triggers a voice alarm, providing timely warnings of potential overheating at the contacts.

4. Partial Discharge Data Integration and Display Function: Connecting to the APD300-L partial discharge monitoring device via an RS485 interface (rear terminals 85 and 86), it can receive and display the discharge amplitude, average value, and number of ultrasonic (AE), radio frequency (TEV), and ultra-high frequency (UHF) discharges in real time. Simultaneously, it displays ambient noise, humidity, and temperature data within the cabinet. The alarm logic is as follows: when the AE amplitude exceeds the preset alarm value and the AE discharge count exceeds 25, the AE alarm flag is set to 1; when the TEV and UHF amplitudes and discharge counts meet the above conditions, the corresponding alarm flags are simultaneously set to 1, providing early warning of partial discharge anomalies.

5. Communication Function: Equipped with dual communication interfaces of RS485 and Ethernet, supporting the MODBUS-RTU communication protocol, it can achieve seamless integration with the field monitoring system, and upload monitoring data and alarm information to the background in real time, which facilitates remote monitoring, data analysis and historical data tracing by staff, and improves the intelligent level of substation management.

2.3.2 Partial Discharge Monitoring Device APD300-L

The APD300-L medium-voltage switchgear partial discharge monitoring device is a multi-dimensional partial discharge monitoring device specifically designed for industrial switchgear. It uses a combination of ultra-high frequency (UHF) sensors, ground wave (TEV) sensors, and ultrasonic (AE) sensors to capture partial discharge signals generated during the operation of electrical equipment, which can effectively determine whether there are hidden dangers such as insulation aging or damage inside high-voltage electrical equipment.

2.3.3 Wireless Temperature Sensor ATE400

The ATE400 wireless temperature sensor can be used in 3~35kV indoor switchgear, including various switchgear such as medium-voltage switchgear, handcart switchgear, fixed switchgear, and ring main units; it can also be used in 0.4kV low-voltage switchgear, including fixed switchgear and drawer switchgear. It can be installed on any heat-generating point inside the cabinet, using wireless data transmission technology to send monitoring data in real time, and then the temperature data is transmitted to a display device or remote monitoring system via a receiving device.

On-site, an ASD500 intelligent control device is installed on the door of the 10KV switchgear instrument room, and an APD300-L partial discharge monitoring device is installed on the wall of the cable room.

On-site installation photos:

3. Conclusion

10kV substations are the core of power distribution, connecting 110kV high voltage and 400V low voltage. Cables, due to prolonged heavy loads and various other reasons, may experience insulation aging, compromising electrical insulation stability and leading to fires or even large-scale power outages.

The significance of partial discharge monitoring in switchgear lies in its ability to reflect the recent discharge situation within the switchgear through discharge amplitude and frequency. If repeated discharges occur consecutively over a period of time, it indicates a potential insulation problem within the switchgear, requiring further inspection and assessment.

For electrical contacts within the switchgear, due to their continuous current carrying capacity, prolonged operation may cause temperature increases. Wireless temperature monitoring devices can monitor temperature changes in electrical contacts in real time, providing timely warnings of abnormal temperature rises and preventing accidents.

For 10kV medium-voltage switchgear, intelligent control devices are also essential. These devices can monitor the physical and electrical quantities of the switchgear and display them on the intelligent control panel. Furthermore, their high-voltage live display function and voice-activated false alarm function further ensure the safety of substation personnel. The intelligent control device can also connect to temperature and humidity sensors, partial discharge sensors, and wireless temperature sensors to display the environment and discharge status inside the cabinet in real time, providing data support for switchgear maintenance.

These three devices together constitute the monitoring of the equipment and environmental conditions of the medium-voltage switchgear, ensuring the safe nd stable operation of the substation switchgear.