JP2013004776A - Mold transformer - Google Patents

Abstract

【Task】
Conventionally, the load current of the mold transformer is measured, and the air cooling fan is controlled by the load current value. In this configuration, there was a case where a large fluctuation in the coil temperature of the transformer did not occur when the load current increased or decreased for a short time. In addition, it is more reliable for the air cooling fan to control the fan at the temperature of the coil of the transformer. However, when a dial thermometer is used, it is a device that displays the temperature and issues an alarm. It was not possible to control other devices.
[Solution]
In the air-cooled mold transformer, the present invention provides a temperature sensor that integrates a temperature sensor and a resistance thermometer in the vicinity of a coil of the mold transformer, and the temperature sensor is connected to a dial thermometer. The temperature is displayed, the resistance temperature detector is connected to the convert meter, the temperature signal is converted into an electrical signal, the control system inputs the electrical signal, and the wind cooling fan placed under the mold transformer is turned on. OFF control to cool the transformer.
[Selection] Figure 1

Description

  The present invention relates to displaying and monitoring the temperature of a mold transformer, particularly an air-cooled mold transformer, and control of an air-cooling fan.

  Mold transformers are widely used as power distribution transformers in buildings and the like for reasons such as flame retardancy, compactness, and low noise.

  Cooling of mold transformers is generally performed by natural convection of air, but when the capacity of the transformer becomes large, it cannot be cooled by natural convection. Cold mold transformer is adopted.

Conventionally, the load current of the mold transformer is measured, and the air cooling fan is controlled by the load current value. In such a configuration, there is a case where the temperature of the coil of the transformer does not fluctuate greatly when the load current increases or decreases in a short time. The air-cooled fan is more reliable to measure the temperature of the coil of the transformer and control the fan with that temperature value, but the dial thermometer itself is a device that displays the temperature and issues an alarm, The dial thermometer itself could not control other devices.
In addition, the resistance thermometer can output numerical values to other devices, but the dial thermometer and the resistance thermometer each have a temperature measuring section, and there is an error in the measured value due to the difference in the measurement location. Was produced.

In the present invention, the temperature sensor is integrated, but a structure close to the configuration of the temperature sensor of the present invention is described in Patent Document 1 (Japanese Patent Laid-Open No. 9-96573).
Furthermore, the structure which measures the temperature of the coil of a transformer is disclosed by patent document 2 (Unexamined-Japanese-Patent No. 9-229775).

JP-A-9-96573 JP-A-9-229775

  In Patent Document 1 (Japanese Patent Laid-Open No. 9-96573), by adopting a configuration in which two types of winding thermometers are collectively inserted into a container, the measurement results coincide with each other. In order to reduce the processing of the container for tightly inserting and attaching to the container, and to contribute to cost reduction, the configuration is composed of a dial thermometer type temperature sensing part 31 of the winding thermometer 3 and a resistance type temperature sensing part. The structure which accommodated the temperature resistance body 32 in the one temperature sensing cylinder 34 is disclosed. However, the configuration in which the temperature sensing unit and the temperature measuring resistance element are integrated as in the present invention is different from Patent Document 1.

  Patent Document 2 (Japanese Patent Application Laid-Open No. 9-229775) describes, as an explanation of the prior art, “the low voltage winding 22 and the high voltage winding 24 are wound outside the iron core 21 via the cooling duct 23, 22 and 24 are respectively molded with resin 25. A temperature sensitive part 26 of the dial thermometer is fixed to the upper part of the cooling duct 23 at a position with a required insulation distance in air. It is disclosed that the temperature display unit 28 of the meter is connected by a temperature sensing unit 26 and a snake tube 27. However, the configuration of Patent Document 2 is different because the temperature is measured via a heat pump.

  In general, there are two types of air-cooled mold transformers that keep the air-cooling fan continuously operated and cool, and ones that operate the air-cooling fan when the self-cooling capacity of the mold transformer is exceeded. The present invention relates to an apparatus for operating a wind-cooling fan when the self-cooling capacity of a molded transformer is exceeded.

  When monitoring the self-cooling capacity of the mold transformer, the load current is measured, and the wind cooling fan is operated when the set current value is exceeded. When the wind cooling fan is controlled using load current because it gradually rises or falls, the timing is shifted, for example, the fan operation is started before the temperature of the coil reaches the air cooling temperature.

  An object of the present invention is to provide a wind-cooled mold transformer that measures temperature data of a coil or the vicinity of a coil, not a conventional load current, and controls a wind-cooled fan using the temperature data.

  In order to achieve the above-mentioned object, the present invention arranges a temperature sensor which integrates a temperature sensor and a resistance thermometer in the vicinity of a coil of a mold transformer, and the temperature sensor is connected to a dial thermometer. The temperature measuring resistor is connected to a convert meter, the temperature signal is converted into an electrical signal, the control system inputs the electrical signal, and the wind cooling fan disposed below the mold transformer It is characterized by controlling.

  The temperature measuring element is disposed near the coil of the mold transformer, measures the ambient temperature near the coil, obtains a relational expression between the ambient temperature near the coil and the coil temperature in advance, Further, the coil temperature is obtained by conversion.

  In addition, a temperature sensor provided with a temperature sensor and a resistance thermometer as a temperature sensor is provided with a hole in the mold part beside the coil of the mold transformer, and the temperature sensor is inserted and disposed in the hole, The temperature sensing unit is connected to a dial thermometer to display the temperature, the resistance temperature detector is connected to a convert meter, the temperature signal is converted into an electrical signal, the control system inputs the electrical signal, and the mold transformer Controls the air cooling fan located at the bottom of the unit.

  According to the present invention, it is possible to grasp an accurate operation state by making the measurement points for measuring the temperature the same and reducing each measurement value error as much as possible. Moreover, the operation of the air cooling fan suitable for the temperature rise of the coil itself can be performed by the analog temperature display by the thermometer and the control by the resistance temperature detector.

  By incorporating a resistance temperature detector in the thermometer instrument section, the individual wiring of the resistance temperature detector can be simplified, and parts can be reduced and workability can be improved.

The air-cooled mold transformer which controls a wind-cooling fan using the temperature sensor of this invention is shown. It is the front view and side view of an air-cooled mold transformer. A temperature sensor and a dial thermometer are shown. It is a fragmentary perspective view when installing a temperature measuring element in a mold transformer and measuring temperature. It is a figure showing the relationship between the atmospheric temperature of the coil vicinity in FIG. 4, and the surface temperature of a coil. It is a figure which shows the temperature measurement state showing the structure of another Example of this invention.

Embodiments of the present invention will be described with reference to the drawings.
Example 1
FIG. 1 shows an air-cooled mold transformer that uses the temperature sensor of the present invention to display the coil temperature or to control and cool the air-cooling fan.

  In FIG. 1, 1 is a mold transformer, 2 is a temperature sensor, 3 is a dial thermometer, 4 is a convert meter, 5 is a control unit for controlling the air-cooling fan 6, and 25 is an alarm device.

Although the temperature measuring sensor 2 will be described later, the temperature measuring sensor 2 uses two types of temperature sensors, that is, a temperature sensing portion and a temperature measuring resistance element, as one body. The temperature sensing unit is connected to a dial thermometer, and is connected to the alarm device 25 from the dial thermometer. The temperature measuring resistance element is connected to the convert meter 4, and the convert meter 4 converts the signal of the temperature measuring resistance element into an electric signal. The convert meter 4 converts a temperature signal into an electric signal, and the convert meter 4 is connected to the control unit 5.
In the control unit 5, the air cooling fan 6 is controlled by a signal obtained by converting the temperature signal into an electric signal. The control system for controlling the air cooling fan 6 is open loop control for turning the air cooling fan 6 on and off according to the value of the temperature measuring sensor 2.

  Next, the structure of the mold transformer 1 is demonstrated using FIG.

FIG. 2A shows a front view of a molded transformer, particularly a three-phase three-leg extra high voltage (hereinafter referred to as extra high) mold transformer, and FIG. 2B shows a side view thereof.
In FIG. 2, 7 is a coil molded with resin, 8 is an iron core formed of a silicon steel plate or an amorphous steel plate, 9 is a tap switching portion, 10... Base, 35, 36 under clamp, and 11 is a primary side terminal. , 12 is a secondary side terminal, 13 is a vibration isolator, and the vibration isolator 13 has a vibration isolating structure so that the vibration of the transformer body is not transmitted to the outside.
Reference numeral 14 denotes the winding start, and 15 denotes the winding end. The wire is used to form a connection by, for example, tapping as shown in FIG. Reference numerals 33 and 34 denote upper clamps, and the mold main body is fixed to the lower clamps 43 and 44.
The coil 7 is molded with resin, and the air-cooling fan 6 is attached to six seats on the front and rear sides of the lower side of the coil 7 so as to be oriented in the direction of the coil 7. The air cooling fan 6 uses a sirocco fan, and the sirocco fan is also called a multi-blade fan. A large number of blades are attached to the rotation direction and used in a relatively low static pressure range.

  Next, the temperature sensor and dial thermometer of the present invention will be described with reference to FIG.

The temperature measuring sensor 2 is provided at the tip of the flexible tube 22 made of material SUS. The tip is formed of a Teflon (registered trademark) heat-shrinkable tube, the size is 5 mm in diameter, and the inside is a SUS pipe. A resistance temperature detector element and a temperature sensing part are inserted into the pipe and integrated.
The resistance temperature detector element uses Pt100 (100Ω at a temperature of 0 ° C.) and employs a single conductor with a three-conductor type.
The three-conductor type is a highly reliable measurement method in which two conductors are connected to one end of the resistance temperature detector element and one conductor is connected to the other end, and the influence of the conductor resistance is removed.

Moreover, if Pt100 is for high temperature, the measurement temperature range is 0-650 degreeC.
The resistance temperature detector element passes through the flexible tube, and a temperature signal is output from the terminals 21 a, 21 b, and 21 c of the dial thermometer 3.
Terminals 21a, 21b, and 21c of the dial thermometer 3 are connected to the convert meter 4, and the convert meter 4 converts the temperature signal of the resistance temperature detector into an electrical signal.
The converted electric signal is sent to the control unit 5 as shown in FIG. 1, and the control unit 5 performs control to drive the air cooling fan when the signal of the resistance temperature detector exceeds a predetermined value. If the predetermined value is not exceeded, the wind cooling fan 6 is stopped and the wind cooling fan 6 is controlled to be turned on and off.

The temperature sensing unit is connected to a dial thermometer, and a temperature memory is displayed on the dial thermometer, and a temperature scale is indicated by a needle so that the temperature can be recognized at a glance.
Moreover, the signal of a temperature sensing part is output to terminal 20a, 20b, and the alarm device 25 is connected to this terminal 20a, 20b. An alarm is issued when the temperature exceeds a predetermined value.

FIG. 4 shows a partial perspective view of measuring the temperature in the vicinity of the coil by installing a temperature measuring element in the extra high-temperature mold transformer.
In FIG. 4, 30 is a primary side high voltage coil, 7 is a secondary side high voltage coil, 31 is an inter-coil air insulation part, and 37 is the air flow of the warmed atmosphere of an inter-coil air insulation part. Reference numeral 32 denotes a support plate for supporting and fixing the temperature measuring sensor, 33 and 34 are upper clamps, 35 is a primary terminal, and 36 is a secondary terminal.
In the extra high-temperature mold transformer, an insulation distance must be secured between the primary high voltage coil 30 and the secondary high voltage coil 7 because of the extra high voltage. Therefore, the temperature measuring sensor 2 cannot be measured by inserting it beside the coil. Therefore, the ambient temperature in the vicinity of the coil is measured at a location away from the coil.

  Further, a relationship between the coil temperature and the ambient temperature in the vicinity of the coil is preliminarily stored, and the air cooling fan is ON / OFF controlled with a value calculated from the ambient temperature.

FIG. 5 shows an example of the relationship (actual measurement) between the coil temperature and the ambient temperature in the vicinity of the coil.
In the characteristic diagram of FIG. 5, the vertical axis represents the temperature rise value (K: Kelvin), the horizontal axis represents the elapsed time (h), the upper characteristic curve represents the coil rise value (K), and the lower characteristic curve represents the dial. The thermometer rise value (K) is represented. Here, the coil rise value indicates the surface temperature of the coil.

In FIG. 5, when the temperature at the dial thermometer gradually increases by 5 to 6K until about 9 hours, the temperature of the coil tends to increase by nearly 20K. Utilizing these characteristics, the correspondence of the coil temperature is calculated from the ambient temperature of the coil, and the air cooling fan is controlled.
(Example 2)
FIG. 6 is a diagram showing another embodiment in which a temperature measuring sensor is installed in a low-voltage mold transformer that is not a general extra high.
In FIG. 6, the temperature sensor 2 is provided with an elongated hole in the coil resin portion near the conductor 40, and a temperature sensor guide 41 is inserted into the hole, and the temperature sensor 2 is inserted and fixed. .
In such a configuration, since the temperature sensing unit and the temperature sensor of the resistance temperature detector element are integrally disposed near the conductor, the temperature of the conductor 40 can be measured with high accuracy without variation. As a result, an accurate temperature can be displayed, and the air cooling fan 6 can be controlled efficiently.

DESCRIPTION OF SYMBOLS 1 ... Mold transformer 2 ... Temperature sensor 3 ... Dial thermometer 4 ... Convert meter 5 ... Control part 6 ... Air-cooling fan 7 ... Coil 8 ... Iron core 9 ... Tap switching part 10 ... Base 11 ... Primary side terminal 12 ··· Secondary side terminal 13 · Vibration isolator 14 · Start of winding 15 · End of winding 20a, 20b · Terminals 21a, 21b, 21c · · · Terminal 22 · Corrugated tube 25 · Alarm device 30 · Secondary side high voltage coil 31 · Air insulation between coils Section 32... Sensor support plate 33 and 34 Upper clamps 43 and 44 Lower clamp 37 Air flow of atmosphere
36 ··· Transformer suspension ear ··· Conductor 41 ··· Guide for sensor 42 ··· Coil resin part

Claims (3)

A temperature sensor that integrates the temperature sensor and resistance thermometer is placed near the coil of the mold transformer,
The temperature sensing unit is connected to a dial thermometer to display the temperature,
The resistance temperature detector is connected to a convert meter, converts a temperature signal into an electrical signal,
The control system receives the electric signal and controls a wind cooling fan disposed on the lower side of the mold transformer. In the air-cooled mold transformer according to claim 1,
The temperature measuring element is disposed near the coil of the mold transformer,
Measure the ambient temperature near the coil,
An air-cooled mold transformer, wherein a relational expression between an ambient temperature and a coil temperature in the vicinity of the coil is obtained in advance, and the coil temperature is calculated from the ambient temperature. A temperature sensor provided with a temperature sensor and a resistance temperature sensor as a temperature sensor is provided with a hole in the mold part next to the coil of the mold transformer, and the temperature sensor is inserted and arranged in the hole,
The temperature sensing unit is connected to a dial thermometer to display the temperature,
The resistance temperature detector is connected to a convert meter, converts a temperature signal into an electrical signal,
The control system receives the electric signal and controls a wind cooling fan disposed on the lower side of the mold transformer.

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