CN107478971A - The device and control method of oil-filled transformer temperature rise test time can be shortened - Google Patents

Abstract

The invention relates to a device and control method capable of shortening the temperature rise test time of an oil-immersed transformer. Its technical characteristics are: it is composed of heat dissipation shields, racks, gears, support rods and bases symmetrically arranged on both sides of the transformer heat dissipation device. , the heat dissipation shutter is covered on the top and side of the heat dissipation device, the heat dissipation shutter is fixed with the rack and can move in the horizontal direction with the rack, the gear is engaged with the rack controlled by the motor, and the support rod is a plurality of , the upper end of each support rod is fixed to the gear axis, and the lower end of each support rod is fixed to the base. The design of the present invention is reasonable. It adopts the method of reducing the heat dissipation of the transformer. By controlling the heat dissipation conditions of the transformer, the heat emitted by the transformer to the external medium is reduced, the oil temperature rise rate is increased and the thermal stability is achieved in a shorter time. The present invention does not require Increasing the input power value will not exceed the normal load capacity of the winding and will not cause local losses to the insulation.

Description

Device and control method capable of shortening temperature rise test time of oil-immersed transformer

technical field

The invention belongs to the technical field of high-voltage testing of transformers, in particular to a device and a control method capable of shortening the temperature rise test time of an oil-immersed transformer.

Background technique

During normal operation, the temperature rise of the oil or winding of the transformer is too high, which will accelerate the aging of the insulating material and shorten the service life of the transformer. The national standard GB1094.2 has made clear and specific regulations on the requirements and methods of the temperature rise test. Through the temperature rise test, it can be verified whether the temperature rise of each part of the transformer meets the requirements of the temperature rise limit. According to the test method in the national standard, the time required for the transformer temperature rise test is generally longer (about 10 to 20 hours). The early stage of the transformer temperature rise test is the process in which the oil temperature rises and reaches stability, which is the main part of the test time. In order to shorten the test time and improve work efficiency, some test units will increase the input power value in the early stage of the test, so as to rapidly increase the winding temperature and calorific value. This method makes the transformer exceed the rated load capacity, causing the temperature of the hot spot of the winding to be too high, and it is easy to cause local overheating and damage to the insulation.

Contents of the invention

The purpose of the present invention is to overcome the deficiencies of the prior art, and propose a device and control method with reasonable design, high efficiency, safety and reliability, which can shorten the test time of oil-immersed transformer temperature rise.

The present invention solves its technical problem and realizes by taking the following technical solutions:

A device capable of shortening the temperature rise test time of an oil-immersed transformer, which is composed of heat dissipation shields, racks, gears, support rods and bases symmetrically arranged on both sides of the transformer heat dissipation device, and the heat dissipation shield covers the heat dissipation device On the top and side, the heat dissipation shield is fixed with the rack and can move horizontally with the rack. The gear is engaged with the rack controlled by the motor. There are multiple support rods, and each support rod The upper end of each support rod is fixed with the gear axis, and the lower end of each support rod is fixed with the base.

There are three support rods and they are evenly distributed on the base.

A control method for a device capable of shortening the temperature rise test time of an oil-immersed transformer, comprising the following steps: during the transformer temperature rise test process, the motor speed is controlled through a preset program, so that the gear drives the rack to move horizontally and drives the heat dissipation shield The area of the plate covering the heat dissipation device changes correspondingly, so as to realize the control and adjustment of the heat dissipation conditions of the transformer.

When controlling the heat dissipation conditions, feedback control is added between the oil temperature and the motor speed, and the motor speed is adjusted in real time according to the oil temperature change, so that the oil temperature gradually rises and stabilizes in the shortest time.

Advantage and positive effect of the present invention are:

1. In order to make the oil temperature of the transformer rise rapidly under the premise of the specified input power value, the present invention adopts the method of reducing the heat dissipation of the transformer. By controlling the heat dissipation conditions of the transformer, the heat emitted by the transformer to the external medium is reduced, and the oil temperature rise speed is increased. And reach thermal stability in a shorter time. The invention does not need to increase the input power value, will not exceed the normal load capacity of the winding, and will not cause local loss to the insulation.

2. The device of the present invention can automatically control the heat dissipation condition of the transformer during the temperature rise test process through the preset program, and the test time can be reduced by 30% to 40%, effectively improving the work efficiency.

Description of drawings

Fig. 1 is a structural front view of the present invention;

Fig. 2 is a side view of Fig. 1;

Figure 3 is the oil temperature rise curve of the transformer under the condition of low temperature Ts when the heat dissipation shutter is removed;

Figure 4 is the oil temperature rise curve of the transformer under the condition of high temperature Ts when the heat dissipation shutter is removed.

detailed description

Embodiments of the present invention will be described in further detail below in conjunction with the accompanying drawings.

A device that can shorten the temperature rise test time of an oil-immersed transformer, as shown in Figure 1 and Figure 2, consists of a heat dissipation shield 1, a rack 2, a gear 3, a support rod 4 and Base 5 constitutes. The heat dissipation shield 1 covers the top and side of the heat dissipation device, and the heat dissipation shield 1 is fixed with the rack 2 and can move along with the rack 2 in the horizontal direction. The gear 3 is meshed with the rack 2, and the rotation of the gear 3 is controlled by a motor. There are a plurality of support rods 4, the upper end of each support rod 4 is fixed to the central axis of the gear 3, and the lower end of each support rod 4 is fixed to the base 5 to play the role of supporting the main body of the device. During the temperature rise test of the transformer, the motor speed is controlled by the preset program, so that the gear 3 drives the rack 2 to move horizontally, and the area covered by the heat dissipation shield 1 changes correspondingly, so as to realize the control and adjustment of the heat dissipation conditions of the transformer.

The control method of the device capable of shortening the temperature rise test time of the oil-immersed transformer of the present invention is controlled according to the oil temperature rise curves of the transformer under different heat dissipation conditions as shown in Fig. 3 and Fig. 4 . Curve S1 is the oil temperature rise curve under the condition that the heat dissipation shutter completely covers the heat sink, and curve S2 is the oil temperature rise curve under the condition that the heat dissipation shield does not cover the heat sink and the heat dissipation device is completely natural. When the temperature Ts is reached, the time required by the curve S1 is shorter than that of the curve S2 (t2-t1). At this time, the heat dissipation shutter is removed to allow the heat dissipation device to dissipate heat naturally, and the transformer oil temperature will be between S1 and S2. The increasing trend reaches a stable temperature Tw. If the temperature Ts is low when the heat dissipation shield is removed, the transformer oil temperature will gradually increase to a stable temperature Tw, as shown in Figure 3; if the temperature Ts is high when the heat dissipation shield is removed, the transformer oil temperature will increase and exceed After the stable temperature Tw is gradually lowered to the stable temperature Tw, as shown in Fig. 4 . If the oil temperature exceeds the stable temperature, it is easy to cause insulation damage. Therefore, when controlling heat dissipation conditions, in order to prevent the oil temperature from exceeding the stable temperature, feedback control will be added between the oil temperature and the motor speed, and the motor speed will be adjusted in real time according to the oil temperature change, so that the oil temperature will gradually rise and reach stability in the shortest time .

Taking a SBH15-M-630/10 transformer as an example, the device provided by this patent is used to conduct a temperature rise test. The data of oil temperature change with time is shown in Table 1.

Table 1 Oil temperature and time in temperature rise test

time (hours) Oil temperature (Celsius) 0 27 1 48 2 60 3 69 4 73.2 5 74 6 74.5 7 74.8

It usually takes about 12 hours for the oil temperature of this type of transformer to reach stability, but it only takes 7 hours to reach stability after using this patented device.

It should be emphasized that the embodiments described in the present invention are illustrative rather than restrictive, so the present invention is not limited to the embodiments described in the specific implementation, and those skilled in the art according to the technical solutions of the present invention Other obtained implementation modes also belong to the protection scope of the present invention.

Claims (4)

1. A device that can shorten the temperature rise test time of an oil-immersed transformer is characterized in that: it is composed of a heat dissipation shield symmetrically arranged on both sides of the transformer heat dissipation device, a rack, a gear, a support rod and a base, and the heat dissipation shield The plate is covered on the top and side of the heat sink, the heat dissipation shield is fixed with the rack and can move horizontally with the rack, the gear is engaged with the rack controlled by the motor, and the support rod is multiple The upper end of each support rod is fixed to the gear axis, and the lower end of each support rod is fixed to the base. 2. The device capable of shortening the temperature rise test time of an oil-immersed transformer according to claim 1, characterized in that there are three support rods and they are evenly distributed on the base. 3. A control method for a device capable of shortening the temperature rise test time of an oil-immersed transformer according to claim 1 or 2, characterized in that it comprises the following steps: during the transformer temperature rise test process, the motor speed is controlled by a preset program so that The gear drives the rack to move horizontally and drives the area of the heat dissipation shield to cover the heat dissipation device to change correspondingly, so as to realize the control and adjustment of the heat dissipation conditions of the transformer. 4. The control method of the device capable of shortening the temperature rise test time of the oil-immersed transformer according to claim 3, characterized in that: when controlling the heat dissipation conditions, feedback control is added between the oil temperature and the motor speed, and according to the oil temperature change Adjust the motor speed in real time to realize the gradual increase and stability of the oil temperature in the shortest time.