Overview

The cable terminals inside switchgear cabinets, as well as the moving and stationary contacts of high-voltage switchgear and connection points of electrical equipment, are vulnerable weak links prone to failure. Due to poor contact or misalignment during insertion in these areas, the contact resistance becomes significantly high. Under high-current conditions, this leads to severe heating at these points, resulting in abnormal terminal temperatures. This, in turn, accelerates oxidation of the contact surfaces, further increasing the contact resistance—a vicious cycle that can ultimately cause serious safety incidents.

Meanwhile, abnormal overheating caused by poor contact at moving and stationary contact points, high-voltage cable joints, and the conductor parts of connectors can significantly accelerate insulation aging, leading to dielectric breakdown. This is also one of the common faults in high-voltage switchgear.

Scope of application

Temperature monitoring for equipment such as high-voltage switchgear contacts and terminals, knife switches, intermediate joints of high-voltage cables, dry-type transformers, low-voltage high-current switchgear, and other environments where temperature measurement is required in related fields.

Function and Working Principle

Wireless temperature measurement technology consists of two main components: a temperature sensor unit and a signal reception and processing terminal instrument. The temperature sensors are installed at high-voltage measurement points or other locations where temperature monitoring is required. The terminal processor can be placed, as needed, in the secondary central control room or another location that is convenient for operators to access. Data is transmitted between these components wirelessly, eliminating the need for physical wiring and thereby avoiding any insulation-related concerns.

Wireless temperature sensor

The temperature sensor is installed at the measurement point and performs signal acquisition and transmission through the following steps: acquiring the temperature signal of the object being measured, sampling and filtering the signal, modulating and amplifying the signal, and then transmitting the signal wirelessly.
Wireless temperature sensors are divided into two types: active and passive.

Sensors are classified into the following categories based on their installation methods:

V. Signal Reception Processor

Signal Reception and Processing Controller Section: This section performs tasks including signal reception, data display, over-limit alarms, data uploading, and data storage. The processing controllers are divided into direct-reception controllers and centralized-reception controllers.

6. Distributed Wireless Temperature Measurement Networking and Station Construction

In certain applications, depending on temperature-measurement requirements, it is necessary to perform real-time temperature monitoring of distributed temperature-sensing devices. The signals are received and processed by a signal-receiving processor, which then uses various communication methods to network the devices and build a wireless temperature-monitoring system. Alternatively, wireless temperature sensors can directly acquire signals and upload them to a centralized data-collection host. Multiple data-collection hosts can then be interconnected via a network and communicate with a workstation platform, thereby establishing a comprehensive temperature-monitoring system.

7. Description of Wireless Temperature Sensor Device Models