The present invention refers to a process and devices for measurement of multiple temperatures, without contact and periodically, in an automatic way, substituting thus way, periodic thermographies in low and medium voltage electric panels, devices, electric equipments, transformers and others. It can also be applied for continually temperature measurements in industrial processes. The new regulations and standards as NR10 and others impede the opening of energized electric panels without an appropriate protection, what endears and hinders the thermography process .

Nowadays to determine if certain electric connection or an electric equipment or other equipments, is suffering heating due any cause, along the time, it is necessary to have visual access to the equipment and being used of a special device, with a Laser pointer, to do measurements point to point, or use a infrared camera to do an image with patterns of colors corresponding to each temperature range. The evident disadvantage of this process is the high consumption of time and specialized personnel, besides risk of accidents and high intervals of time among the measurements. In the case of temperature measurements in processes are usually used probes that get in touch with the body or substance to be measured.

The presented process allows to accomplish measurements in real time or with programmable intervals of time of the electric devices and connections internally to low voltage, medium voltage and high voltage electric panels and also in stand alone equipments, as transformers or industrial processes. The ultra high isolation between the sensor and the measured devices due to non contact measuring method, allow its use for measurement of energized devices without risk for the system or people and without interfering with the safety standards, as arcing resistance and others. An additional advantage is that it can, with a single HMI (Human Machine Interface) device, as protection relay, PLC or computer, to measure hundreds of different points, with the outputs of the sensor connected by a optical fiber net or freely through a wireless radio net (Zigbee) or even with a wired net, RS485 or CAN depending of the application.

The process is based in the principle of measuring the energy irradiated by the body to be measured, in the infrared wavelength range. Each sensor still measures, at the same time, the temperature of his body, in other words, of the surrounding air.

In the drawing 1 the sensor (1) can be observed measuring one target (2) with certain opening angle, presenting several distances with the areas of equivalent measurements and in the drawing 2 an example of a sensor (1) can be observed measuring one target area (2) with three connections. Several opening angles are available.

In the drawing 3 the optical fiber connection principle can be observed. This connection obtain ultra high electric isolation. The relay (1) connected with the group of sensor (2), that can go from 1 to 125, using a optical fiber communication proprietary protocol. Each sensor can be programmed and commanded directly by the HMI, in this case a protection relay (1). The communication protocol includes a system to check the integrity of the series connection (Hearthbeat), in this case the optical fiber, with automatic detection of the point of eventual defect of the net, showing in a map in the display of the relay( 1 ) the sensor ones that are answering or are not answering. One type of measurement sensor of the system can be seen in the drawing 4 being constituted of an articulated base (1), facilitating the aim to the target, a lastic body (2), an electronic device containing the sensor and auxiliary circuits (3), a voltage source or batteries (4) and one optional connector (5) for the case of feeding (AC or CC - without batteries). The calibration of the sensor, during the production, is done by comparison with the measurement in a standard black body.

In the system with polymeric or glass optical fibers, the temperature data and others are transported by the optical fibers between the device of presentation of the data and protection and the sensors, each one with a sequential numeric address. In the drawing 5, we can see two nets of sensor (1) linked by the optical fibers (2) in the measurement relay ( 1 ) with two channels .

In the system with radio net (wireless) the sensor, each one with a specific, sequential numeric address, communicate with the device of data presentation and protection, without physical connection, being used a radio connection. In the drawing 6 we can see the sensors (1), the graphic representation of the radio waves (2) and the protection relay (3 ) .

The system can still use tubular sensors with wired net connection in Modbus or CAN or others protocols. In the drawing 7 we can see the body of the sensor (1), the front part where is the infrared sensor (2), the communication port for parameter changing or connection to the net, type mini USB (3), the optional cable for connection to the net (4) and the internal wires to the cable (5). In the drawing 8 we can see an special protection relay (1 ) connected to up two nets of sensor (2) and (3).