JPH0343815Y2 - - Google Patents

Description

[Detailed description of the invention] (Field of industrial application) This invention relates to an abnormality detection device in a cooling device using a refrigerant that utilizes the latent heat of vaporization of electrical equipment such as a rectifier, and in particular, it relates to an abnormality detection device for a cooling device using a refrigerant that uses the latent heat of vaporization of electrical equipment such as a rectifier. This invention relates to means for early detection of temperature rise.

(Prior Art) As a cooling device for electrical equipment such as a silicon rectifier, a device that utilizes the latent heat of vaporization of, for example, a fluorocarbon liquid is known. As shown in Fig. 2, a refrigerant R such as fluorocarbon liquid is sealed in a steel tank 1, and the rectifier unit 2 immersed in the fluorocarbon liquid is cooled by the latent heat of vaporization of the fluorocarbon liquid. be. In this case, the temperature rise of the fluorocarbon liquid is given by the product of the thermal impedance of the tank 1 and the radiator 3 relative to the atmosphere multiplied by the amount of heat generated.

By the way, in the above cooling device, if air enters the device due to poor airtightness of the tank 1 or the radiator 3, the air will fill the upper part of the radiator 3, impairing the cooling effect of the radiator 3. As a result, the thermal impedance of the tank and radiator increases, and the temperature of the Freon fluid also increases. This phenomenon immediately raises the temperature of the silicon rectifier unit 2, which not only makes normal operation impossible, but also may cause destruction of the silicon rectifier element in some cases.

Conventionally, as a protection device against the temperature rise of the fluorocarbon liquid, measures have been taken such as attaching a temperature sensor 4 to the outer wall of the tank 1 and issuing an alarm using a temperature relay 5 connected to the temperature sensor 4. Here, the set value of the temperature sensor 4 is set to a temperature that is the maximum room temperature in summer, the maximum temperature at maximum load, and a slight margin.

However, conventional protection devices are capable of detecting gradual temperature increases due to slow leaks, and do not have the ability to detect slow leaks early and take preventive measures.

Therefore, this invention makes it possible to detect gradual temperature rises due to slow leaks at an early stage in cooling systems for electrical equipment that use refrigerants that utilize latent heat of vaporization, and to take preventive measures against them. The purpose is to provide a cooling device.

(Means for Solving the Problems) In order to achieve the above object, the abnormality detection device for a cooling device for electrical equipment of this invention is intended to be used in a cooling device for electrical equipment using a refrigerant that utilizes latent heat of vaporization. means for simulating the temperature of the refrigerant from the value of the voltage or current and the thermal impedance of the refrigerant; means for correcting the simulated value based on the room temperature; and a signal indicating the corrected simulated value and the actual value. and means for comparing the refrigerant temperature with a signal indicating the temperature of the refrigerant.

(Function) The abnormality detection device for the cooling device of electrical equipment of this invention simulates the temperature of the refrigerant based on the above configuration, and generates a signal indicating the value corrected at room temperature and a signal indicating the actual temperature of the refrigerant. Since abnormalities in the cooling device are detected by comparing the values, even gradual temperature rises caused by slow leaks can be detected at an early stage.

(Example) Referring to FIG. 1, an example in which this invention is applied to an abnormality detection device for a cooling device for a silicon rectifier will be described in detail below.

The part 10 surrounded by the dashed-dotted line in FIG.
This is the simulation and comparison section that is the main feature of this device, and the sections designated by numerals 1 to 4 are the second
Similar to the device shown in the figure, a steel tank, a silicon rectifier unit, a radiator and a temperature sensor are shown, and 6 is a power supply for the silicon rectifier.

11 is a detector for detecting the load current of the silicon rectifier, 12 is a room temperature detector, 13 is a freon tank temperature detector connected to the temperature sensor 4, 11a, 1
2a and 13a are respectively the load current detector 1
1. An A/D converter that converts the output analog quantities of the room temperature detector 12 and the freon tank temperature detector 13 into digital quantities.

As an example of means for detecting the voltage or current value of the electrical equipment to be cooled in order to simulate the temperature of the refrigerant R (in this example, Freon liquid), the output of the A/D converter 11a is used for heat loss calculation. The forward voltage drop characteristic (Vf
The heat losses of the silicon rectifier unit 2 are calculated on the basis of the characteristics). On the other hand, the thermal impedance of the refrigerant is set by a thermal impedance setting device 16. The freon temperature is simulated in the temperature simulation device 17 from the output of the heat loss calculation device 14, that is, the value of the load current of the silicon rectifier unit 2 and the value of the thermal impedance of the freon output by the thermal impedance setting device 16. Here, a signal obtained by A/D converting the output of the room temperature detector 12 is further input to the temperature simulation device 17, and the above simulation value is corrected based on the room temperature. Therefore, the output of the temperature simulation device 17 indicates a value obtained by correcting the temperature rise of the fluorocarbon by the room temperature when the temperature of the fluorocarbon tank 1 and the forward voltage drop of the silicon rectifier are normal. The signal indicating this value and the output of the freon temperature detector 13 are
The comparator 18 compares the D-converted signal indicating the actual fluorocarbon temperature to determine whether there is a gradual rise in the fluorocarbon temperature due to air leaks in the fluorocarbon tank 1, etc. Based on this determination result, an alarm system is activated. Appropriate preventive measures will be taken, such as issuing a warning from 19.

With the above-mentioned means, it is possible to detect a gradual rise in the temperature of freon due to air leaks, etc.
Generally, air leaks from the Freon tank 1 are very gradual, so if this is detected midway and appropriate preventive measures are taken, problems such as sudden stoppage of electrical equipment can be avoided.

The above simulation may be performed continuously, but since the phenomenon of air leakage is gradual as described above, it may be performed intermittently. In this case, the time required for simulation is 1 Freon tank.
The thermal time constant of is a rough guide. The simulation and comparison section 10 described above can be constructed from a microcomputer, a sequencer, a digital relay, etc., but the hardware can be particularly simplified if the computer is shared with a digital relay, etc.

This invention can be applied not only to the silicon rectifier cooling device described above, but also to abnormality detection in cooling devices for electrical equipment such as transformers and reactors.

(Effects of the invention) As mentioned above, according to this invention, the refrigerant temperature is simulated, and a signal indicating the value corrected at room temperature is compared with a signal indicating the actual refrigerant temperature to determine the temperature of the cooling system. Because it detects abnormalities, it is possible to early detect gradual temperature rises caused by slow leaks, etc., and it is possible to take early preventive measures. It can prevent failure of electrical equipment.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an embodiment of an abnormality detection device for a cooling device for electrical equipment according to the present invention, and FIG. 2 is a schematic diagram of a conventional temperature rise detection device for a cooling device for electrical equipment. Explanation of symbols, 1: Tank, 2: Silicon rectifier unit, 3: Radiator, 4: Temperature sensor, 1
1: Load current detector, 12: Room temperature detector, 13:
Temperature detector, 14: Heat loss calculation device, 15: Vf
Characteristic setting device, 16: thermal impedance setting device, 17: temperature simulation device, 18: comparator, R: Freon liquid as refrigerant.

Claims (1)

[Claims for Utility Model Registration] A cooling device for electrical equipment using a refrigerant that utilizes latent heat of vaporization, comprising means for simulating the temperature of the refrigerant from the voltage or current value of the electrical equipment to be cooled and the thermal impedance of the refrigerant; An abnormality detection device for a cooling system for electrical equipment, comprising means for correcting a simulated value based on room temperature, and means for comparing a signal indicating the corrected simulation value with a signal indicating the actual refrigerant temperature. .