JPS5840413B2 - Kanshikiseiyuudoukino Hogohoushiki - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a temperature-controlled protection system for dry static inductors such as dry air-cooled transformers and reactors.

In the conventional protection method of dry air-cooled stationary inductors by temperature control, the temperature is generally controlled by measuring the temperature of the exhaust air of the cooling air with a thermometer, and operation is performed based on this temperature. It provided an alarm and protected the inductor itself.

However, in this conventional method, the time constant of the temperature rise of the exhaust air is so large that it can last for several hours, so the temperature rise due to stopping of the cooling air, the entry of harmonic components into the circuit, and the rapid and local rise due to overcurrent, etc. However, it was not possible to promptly detect abnormal temperature rises, and it was not possible to sufficiently prevent accidents such as burnout of the inductor body.

In addition, some protection methods have been implemented that directly measure the temperature of the inductor windings or conductors to control the temperature, but this conventional method has drawbacks that make it impractical due to the complexity of handling and maintenance. there were.

The purpose of the present invention is to eliminate the above-mentioned drawbacks of the prior art, and to quickly detect localized temperature increases with short time constants that occur during abnormalities such as temperature increases due to stopping of cooling air or harmonic currents in static inductors. To provide a simple protection method for a dry static inductor that can reliably prevent burnout of the inductor body.

The present invention provides a magnetic body equipped with a temperature sensing element at a predetermined position in the leakage magnetic field of a dry air-cooled stationary inductor, and maintains the magnetic body at a specified temperature by wind cooling at all times. The inductor body is characterized by detecting a rapid local temperature rise in the magnetic body during an abnormality such as temperature rise due to stoppage, ingress of harmonic components, or overcurrent to prevent burnout of the inductor body. This is a protection method for dry static inductors.

Hereinafter, the present invention will be explained in detail according to the drawings.

FIG. 1 is a front view showing an embodiment of the protection system for a dry air-cooled interphase reactor according to the present invention, and FIG.
The figure is a side view thereof.

In these Figures 1-2, 1 is a winding, 2a is a yoke fastener, 2b is a body fastener, 3 is an iron core, 4 is a cooling fan, and 5
is a wind guide, 6 is a thermometer, and 7 is a magnetic material that becomes a local temperature source.

FIG. 3 is an example of a leakage magnetic flux distribution diagram along the yoke fastener 2a of FIG. 1.

FIG. 4 is a block diagram showing the connection of the magnetic body 7 in FIG.
8 in the figure is a temperature sensor (temperature sensing element), 9 is a thermometer, 10
is an alarm device.

In Figures 1 and 2, the dry air cooling interphase reactor includes a winding 1 through which current flows, an iron core 3, yoke clamps 2a and fasteners 2b that tighten the iron core 3, and a cooling fan 4 and a cooling fan 4 that cool these bodies. It consists of a wind guide 5 and a thermometer 6 for measuring the temperature of the cooling medium surrounding the main body.

A small magnetic body 7 serving as a temperature source is installed near the maximum magnetic flux position B of the leakage magnetic flux distribution (FIG. 3) along the yoke clamp 2a of this reactor.

In FIG. 4, a temperature sensor (temperature sensing element) 8, for example, a thermocouple, is attached to the magnetic body 7 to detect the temperature of the magnetic body, and the output of the temperature sensor 8 is guided to a thermometer 9. Connect the output to the alarm device 10.

With such a configuration, the magnetic body 7 is exposed to a leakage magnetic field, so it generates heat due to iron loss, and the amount of heat generated increases in proportion to the power of the magnetic flux density and frequency passing through the magnetic body 7.

Therefore, in a steady state, this magnetic body 7 is cooled by cooling air together with the conductor (winding) 1 and iron core 3, etc., and is maintained at a certain temperature within the range of temperature, and in this state, the reactor operates normally. Driving continues.

Then, when the cooling air stops due to a failure of the cooling device, or an abnormal operating condition occurs such as harmonic components entering the circuit or overcurrent, the temperature of the magnetic body 7 rapidly rises to an extreme level.

In other words, if the cooling air stops due to a failure of the cooling device, the magnetic body 7, which generates heat due to leakage magnetic flux when energized, will naturally circulate the cooling air, which will impair the cooling effect and cause a sudden rise in temperature. When an overcurrent flows, the density of the leakage magnetic flux becomes higher than when the current is applied, and the magnetic material interlinked with this leakage magnetic flux causes a rapid temperature rise in a short period of time.

Since the time constant of this temperature rise is the time constant of the (temperature rise) of the magnetic material in the leakage magnetic field, it is, for example, about several minutes to ten-odd minutes, which is significantly smaller than the temperature rise time constant of each part of the reactor body.

The temperature of the magnetic body 7 is constantly monitored by a temperature sensor 8 and a thermometer 9 attached to the magnetic body 7, and when a predetermined temperature is exceeded, an alarm is issued by an alarm device 10.

In this way, by constantly monitoring the temperature of the magnetic body 7, which causes a rapid local temperature rise during abnormal operation of the reactor, this magnetic body 7 can be Since abnormal conditions can be detected with a significantly small time constant, burnout accidents of the reactor body can be prevented.

As a result, in an actual dry air cooling phase reactor,
We have confirmed that it is possible to reliably detect and protect against localized abnormal temperature rises due to stoppage of cooling air and increased ripple, which could not be protected by conventional exhaust air temperature measurement alone, within a few minutes.

Although the above embodiments have been described in the case of an interphase reactor, this method can be similarly applied to other dry type static inductors including transformers.

In this case, the magnetic body 7 may be placed at an appropriate position within the leakage magnetic flux.

As described above, according to the protection method of the dry static inductor of the present invention, a magnetic body is provided at a predetermined position in the leakage magnetic flux, and by detecting a rapid abnormal temperature rise of the magnetic body, the cooling air is stopped and the harmonics are removed. It is possible to easily and reliably prevent and protect the inductor body from burning out in the event of an abnormality such as ingress of components or overcurrent.

[Brief explanation of the drawing]

FIG. 1 is a front view showing an embodiment of the dry static inductor protection system according to the present invention, FIG. 2 is a side view, and FIG. 3 is a leakage flux distribution diagram along the yoke clamp 2a of FIG. 1. FIG. 4 is a block diagram showing the connection of the magnetic body 7 of FIG. 1. Explanation of symbols, 1... Conductor, 2a... Fastener, 3... Iron core, 4... Cooling fan, 7... Magnetic Body, 8... Temperature sensing element, 9
...Thermometer, 10... Alarm device.

Claims (1)

[Claims] 1. In a protection system for a dry static inductor consisting of a static inductor main body including a winding conductor and an iron core, and an air cooling means for cooling the static inductor main body, at a predetermined position within the leakage flux of the static inductor main body A dry static inductor is provided with a magnetic body equipped with a temperature sensing element, and the static inductor body is protected by detecting a local temperature generated in the magnetic body which is significantly smaller than the temperature time constant of the inductor body. Protection method.