CN207009220U - A device for cooling a dry-type transformer by using an air duct type air conditioner and installing an air duct - Google Patents

Abstract

A kind of device to be cooled using air-duct-type air-conditioner installation guide duct to dry-type transformer, it is characterized in that, it is described using air-duct-type air-conditioner install additional guide duct be to the device that dry-type transformer cools freezed using air-duct-type air-conditioner caused by cold air be connected to plenum chamber via pipeline and led to by guide duct below dry-type transformer heat dissipation channel, then directly from heat dissipation channel by so as to realize the automatic forced wind cooling temperature lowering to dry-type transformer coil.And the cooling activation control of air-duct-type air-conditioner is controlled by two sets of autonomous control systems：First, air-duct-type air-conditioner carries the indoor circumstance temperature NTC of temp testing controlling system to switchgear house or transformer station's indoor temperature detection, according to the start and stop for the control air-duct-type air-conditioner that imposes a condition；Second, dry-type transformer coil temp testing controlling system coil temperature transducer PT100 detects to dry-type transformer coil temperature, according to the control auxiliary reclay that imposes a condition, the start and stop of simulation air-conditioning dedicated temperature sensor circuit control air-duct-type air-conditioner are switched to.

Description

A device for cooling a dry-type transformer by using an air duct type air conditioner and installing an air duct

technical field

The utility model relates to a device for cooling a dry-type transformer by adopting an air-duct type air conditioner and installing an air-guiding pipe.

Background technique

In the power supply system, dry-type transformers have higher requirements for fire protection and explosion protection in high-rise buildings, commercial centers, airports, chemical plants, nuclear power plants, and industrial and mining enterprises due to their excellent characteristics such as environmental protection, flame retardancy, impact resistance, and maintenance-free. High places have been widely used. Due to the constraints of the dry-type transformer manufacturing process, dry-type transformers are suitable for substations and distribution stations with a voltage of 35kVA and below and a single capacity of 2500kVA and below. At present, the mainstream cooling methods of dry-type transformers include natural air circulation cooling and fan forced air circulation cooling. Natural air circulation cooling is only suitable for dry-type transformers with small capacity and small load; fan forced cooling is suitable for dry-type transformers with large capacity and load, but fan forced air circulation cooling cannot meet the capacity, large load and load The cooling requirements of dry-type transformers with large changes, and the low efficiency of cooling fans and high failure rate may easily cause the transformer to dissipate heat in time, and the temperature rise is too high, which seriously affects the service life and safe, reliable and economical operation of dry-type transformers.

Utility model content

The purpose of this utility model is to solve the above-mentioned dry-type transformer fans forced air circulation cooling can not meet the cooling requirements of dry-type transformers with large capacity and load and large load changes, resulting in untimely heat dissipation of the transformer, high temperature rise, serious Affecting the service life of dry-type transformers and safe, reliable, and economical operation, the utility model provides a new type of cooling device for dry-type transformers. Lead to the bottom of the heat dissipation channel of the dry-type transformer, and then flow out through the internal heat dissipation duct of the transformer, basically all dissipate in the closed transformer cabinet, so that the temperature of the transformer working environment is reduced, which is beneficial to the overall convection and radiation cooling of the dry-type transformer, thereby realizing The dry-type transformer can quickly and effectively cool down, prolong the service life of the dry-type transformer and improve the load capacity.

The technical scheme of the utility model is: a device for cooling dry-type transformers by using air-duct air conditioners and installing air guide pipes. The device for cooling dry-type transformers by using air-duct air conditioners The 17°C cold air generated by the tube-type air-conditioning refrigeration is connected to the static pressure box through the pipeline and guided to the bottom of the heat dissipation channel of the dry-type transformer through the air duct, flows out through the heat dissipation air channel inside the transformer, and basically dissipates in the transformer cabinet. The temperature reduction of the working environment of the transformer is beneficial to the overall convection and radiation cooling of the dry-type transformer, so as to realize efficient and clean forced air cooling of the dry-type transformer coil, while the cooling start and stop control of the ducted air conditioner is controlled by two independent control systems Composition: First, the indoor ambient temperature NTC of the ducted air conditioner with its own temperature measurement control system detects the indoor temperature of the power distribution room or substation, and controls the start and stop of the ducted air conditioner according to the set conditions; the second is the temperature measurement of the dry-type transformer coil The coil temperature sensor PT100 in the control system detects the coil temperature of the dry-type transformer, controls the intermediate relay according to the set conditions, and switches to the analog air-conditioning special temperature sensor circuit to control the start and stop of the ducted air conditioner.

The device for cooling a dry-type transformer by adding an air duct to an air duct air conditioner is described. The air duct type air conditioner refrigeration start-stop control system and the intermediate relay of the device are switched to a dedicated multi-turn potentiometer for simulating an air conditioner. The temperature sensor circuit works as:

(a) The temperature sensor dedicated to air conditioners is a negative temperature coefficient thermistor, referred to as NTC. Its resistance decreases as the temperature rises and increases as the temperature decreases. The resistance value at the nominal resistance of 25°C is generally 10 KΩ- 50KΩ;

(b) The temperature setting range of the air conditioner is -30°C, the air conditioner does not work when the ambient temperature is lower than 15°C, and does not work when the ambient temperature is higher than 30°C;

(c) The normal coil temperature of the dry-type transformer is about 45°C when it is running without load, which is mainly caused by the heat transferred by the iron core. The temperature detected by the coil during the operation of the dry-type transformer cannot be directly used to control the start and stop of the air conditioner;

(d) The dry-type transformer temperature controller uses a PT100 temperature sensor to detect the temperature of the dry-type transformer coil. When the temperature value is higher than the sum of the set target value and the return difference, the KA1 coil of the dry-type transformer thermostat internal relay is energized. The normally open contact KA1 is closed, the switching intermediate relay KA6 is energized to work, and the two pairs of normally closed contacts KA6-1 and KA6-2 connected in series to the air conditioner special temperature sensor NTC circuit are disconnected, and are connected to the air conditioner special temperature sensor NTC at the same time The two pairs of normally open contacts KA6-3 and KA6-4 of the circuit are closed, the start signal of the air duct air conditioner is switched to the temperature sensor circuit dedicated to the analog air conditioner, the air conditioner is started, and the refrigeration work begins; when the temperature of the dry-type transformer coil drops to the set target When the value minus the temperature value of the return difference, the coil of the internal relay KA1 of the dry-type transformer thermostat loses power, its normally open contact KA1 changes from closed to open, and the intermediate relay KA6 loses power, which is connected in series to the NTC loop of the air-conditioning special temperature sensor The two pairs of normally closed contacts KA6-1 and KA6-2 return to the closed state, and at the same time, the two pairs of normally open contacts KA6-3 and KA6-4 connected to the NTC circuit of the air-conditioning special temperature sensor change from closed to open, and the air duct The starting signal of the type air conditioner is restored to the special temperature sensor circuit of the air conditioner, and the air conditioner stops working;

(e) The resistance value of the precision multi-turn potentiometer R is adjusted to be slightly lower than the resistance value of the temperature sensor when the cooling start-up temperature set by the ducted air conditioner is 26°C. The ducted air conditioner displays a temperature slightly higher than 26°C, which is set according to the actual situation.

The device for cooling a dry-type transformer by adding an air duct to an air duct air conditioner, the selection, installation and start-stop parameter setting of the air duct air conditioner of the device are as follows:

(a) According to the volume of the transformer room where the dry-type transformer to be cooled is located and the heat production of the power distribution room or substation, select a ducted air conditioner with an appropriate cooling capacity;

(b) The indoor unit of the ducted air conditioner is installed near the dry-type transformer. The shorter the air supply distance, the higher the efficiency, and the better the cooling effect of the dry-type transformer coil;

(c) A static pressure box is installed at the air outlet of the ducted air conditioner, and six air guide pipes are separated to connect to the lower opening of the heat dissipation channel on both sides of the three sets of coils of the dry-type transformer;

(d) Setting of start-stop parameters for ducted air conditioners:

One is the indoor ambient temperature NTC of the ducted air conditioner with its own temperature measurement control system to detect the indoor temperature of the power distribution room or substation. The temperature value is set according to the actual situation;

The second is that the dry-type transformer coil temperature measurement control system is in the automatic cooling state of the ducted air conditioner, and the resistance value of the precision multi-turn potentiometer R in the special temperature sensor circuit for the analog air conditioner is adjusted to be slightly smaller than when the temperature of the ducted air conditioner is 26°C The resistance value of the temperature sensor, and at the same time set the start-stop target value of the dry-type transformer coil temperature measurement control system to 50°C, and the start-stop target return difference value is 5°C. At this time, the detection temperature of the dry-type transformer coil temperature measurement control system reaches 55°C Refrigeration starts when the coil temperature drops to 45°C and stops when the coil temperature drops to 45°C.

Compared with the prior art, the utility model has the following beneficial effects:

The utility model adopts an air duct type air conditioner and installs an air guide pipe to cool down the dry-type transformer, which solves the problem that the forced air circulation cooling of the conventional fan of the dry-type transformer cannot meet the requirements of the dry-type transformer with large capacity and load and large load changes. Due to the cooling requirements of the dry-type transformer, the heat dissipation of the dry-type transformer is not timely, and the temperature rise is too high, which seriously affects the service life and safe, reliable and economical operation of the dry-type transformer. When the dry-type transformer is fully loaded, the load capacity of the dry-type transformer can be increased by at least 30%.

Description of the drawings:

Fig. 1 is a schematic diagram of the system structure of a device for cooling a dry-type transformer by using an air-duct air conditioner and adding an air duct.

Figure 2 is a schematic diagram of the three-phase coil structure of a dry-type transformer;

Fig. 3 is a schematic diagram of the structure of six air guide pipes respectively leading to the lower openings of the heat dissipation channels of the three groups of coils;

Fig. 4 is a schematic diagram of the arrangement structure of the air ducts 1 and 2.

Figure 5 is a wiring diagram of the peripheral circuit of the dry-type transformer temperature controller.

Figure 6 is an intermediate relay air duct air conditioner temperature control circuit.

Fig. 7 is the heating power curve of SCB10-1600/10 dry-type transformer under different loads.

Among them: 1 Ducted air conditioner, 2 Ducted air conditioner indoor unit, 3 Static pressure box, 4 Self-contained ducted internal temperature measurement system, 5 Setting the starting conditions for ducted air conditioner cooling, 6 Satisfying the ducted air conditioner refrigeration Start-up conditions, 7 start-up of ducted air conditioner refrigeration, 8 dry-type transformer temperature controller, 9 set the start-stop target value and start-stop target hysteresis of the dry-type transformer temperature control switch, 10 meet the start-up conditions of the temperature control switch, 11 intermediate relay Action, 12 transformer coils, 13 PT100 thermal resistors, 14-19 air ducts, 20 dry-type transformer cooling channels, 21 dry-type transformer cores.

detailed description:

Below in conjunction with specific embodiment the utility model is described in further detail:

Referring to the accompanying drawings 1-7, the utility model is a device for cooling a dry-type transformer using a ducted air conditioner with an air guide tube. The device is to use the cold air generated by the air duct type air conditioner to be connected to the static pressure box through the pipeline, lead it to the bottom of the heat dissipation channel of the dry transformer through the air guide pipe, and then flow out through the heat dissipation air channel inside the transformer, and basically all dissipate in the closed In the transformer cabinet, the temperature of the working environment of the transformer is reduced, which is beneficial to the overall convection and radiation cooling of the dry-type transformer, thereby realizing efficient and clean forced air cooling of the dry-type transformer coil, and the cooling start-up control of the ducted air conditioner It is controlled by two sets of independent control systems: one is the indoor environment NTC of the ducted air conditioner with its own temperature measurement control system to detect the indoor temperature of the power distribution room or substation, and control the start and stop of the ducted air conditioner according to the set conditions; In the transformer coil temperature measurement control system, the coil temperature sensor PT100 detects the temperature of the dry transformer coil, controls the intermediate relay according to the set conditions, and switches to the analog air conditioner special temperature sensor circuit to control the start and stop of the air duct type air conditioner.

The device for cooling a dry-type transformer by adding an air duct to an air duct air conditioner is described. The air duct type air conditioner refrigeration start-stop control system and the intermediate relay of the device are switched to a dedicated multi-turn potentiometer for simulating an air conditioner. The temperature sensor circuit works as:

(a) The temperature sensor dedicated to air conditioners is a negative temperature coefficient thermistor, referred to as NTC. Its resistance decreases as the temperature rises and increases as the temperature decreases. The resistance value at the nominal resistance of 25°C is generally 10 KΩ- 50KΩ;

(b) Usually the temperature setting range of the air conditioner is -30°C, the air conditioner does not work when the ambient temperature is lower than 15°C, and does not work when the ambient temperature is higher than 30°C;

(c) When the dry-type transformer is running without load, the normal coil detection temperature is about 45°C, and the coil detection temperature when the dry-type transformer is running cannot be directly used to control the start and stop of the air conditioner;

(d) The dry-type transformer temperature controller uses a PT100 temperature sensor to detect the temperature of the dry-type transformer coil. When the temperature value is higher than the sum of the set target value and the return difference, the KA1 coil of the dry-type transformer thermostat internal relay is energized. The normally open contact KA1 is closed, the switching intermediate relay KA6 is energized to work, and the two pairs of normally closed contacts KA6-1 and KA6-2 connected in series to the air conditioner special temperature sensor NTC circuit are disconnected, and are connected to the air conditioner special temperature sensor NTC at the same time The two pairs of normally open contacts KA6-3 and KA6-4 of the circuit are closed, the start signal of the air duct air conditioner is switched to the temperature sensor circuit dedicated to the analog air conditioner, the air conditioner is started, and the refrigeration work begins; when the temperature of the dry-type transformer coil drops to the set target When the value minus the temperature value of the return difference, the coil of the internal relay KA1 of the dry-type transformer thermostat loses power, its normally open contact KA1 changes from closed to open, and the intermediate relay KA6 loses power, which is connected in series to the NTC loop of the air-conditioning special temperature sensor The two pairs of normally closed contacts KA6-1 and KA6-2 return to the closed state, and at the same time, the two pairs of normally open contacts KA6-3 and KA6-4 connected to the NTC circuit of the air-conditioning special temperature sensor change from closed to open, and the air duct The starting signal of the type air conditioner is restored to the special temperature sensor circuit of the air conditioner, and the air conditioner stops working;

(e) The resistance value of the precision multi-turn potentiometer R is adjusted to be slightly smaller than the resistance value of the temperature sensor when the cooling start-up temperature set by the ducted air conditioner is 26°C. The temperature displayed by the ducted air conditioner is slightly higher than 26°C, and the temperature value is set according to the actual situation.

The device for cooling a dry-type transformer by adding an air duct to an air duct air conditioner, the selection, installation and start-stop parameter setting of the air duct air conditioner of the device are as follows:

(a) According to the volume of the transformer room where the dry-type transformer to be cooled is located and the heat production of the power distribution room or substation, select a ducted air conditioner with an appropriate cooling capacity;

(b) Ducted air conditioner indoor unit (2) is installed near the dry-type transformer. The shorter the air supply distance, the higher the efficiency, and the better the cooling effect of the dry-type transformer coil;

(c) A static pressure box (3) is installed at the air outlet of the ducted air conditioner, and six air guide pipes (14, 15, 16, 17, 18, 19) are separated to connect to the three sets of coils of the dry-type transformer (phase A, B phase, C phase) the position of the lower opening of the heat dissipation channel;

(d) Setting of start-stop parameters for ducted air conditioners:

One is the indoor ambient temperature NTC of the ducted air conditioner with its own temperature measurement control system to detect the indoor temperature of the power distribution room or substation. The temperature value is set according to the actual situation;

The second is that the dry-type transformer coil temperature measurement control system is in the automatic cooling state of the ducted air conditioner, and the resistance value of the precision multi-turn potentiometer R in the special temperature sensor circuit for simulating the air conditioner is adjusted to be slightly smaller than the temperature of the ducted air conditioner at 26°C. The temperature value is set according to the actual situation when the resistance value of the temperature sensor is set. At the same time, the start-stop target value of the dry-type transformer coil temperature measurement control system is set to 50°C, and the start-stop target hysteresis value is 5°C. At this time, the dry-type transformer coil The temperature measurement and control system detects that the refrigeration starts when the temperature reaches 55°C, and stops when the coil temperature drops to 45°C.

The application of the device for cooling the dry-type transformer by using the air-duct type air conditioner and installing the air-guiding pipe in the utility model is to reduce the power loss by precisely controlling the working coil of the dry-type transformer in the substation/distribution room, thereby effectively reducing the temperature. Prolonging the service life of dry-type transformers is suitable for the cooling control of dry-type transformers in substations and distribution stations with a voltage of 35kV and below and a single capacity of 2500kVA and below, thereby reducing power loss, effectively extending the service life of dry-type transformers, and improving dry-type transformers at the same time. The load of the dry-type transformer is at least 30%, and the number of dry-type transformers can be reasonably reduced under safe and reliable conditions, thereby saving the basic electricity expenses of dry-type transformers.

After adopting a device of the utility model that adopts the air duct type air conditioner and installs the air duct to cool the dry-type transformer, unexpected good results have been obtained:

1. After adopting a device of the utility model that uses an air duct type air conditioner to install an air guide pipe to cool down a dry-type transformer, the coil temperature of a dry-type transformer with a large capacity and load and a large load change is accurately controlled. Control can effectively prolong the service life.

The design rated load rate of the dry-type transformer is generally 80%, that is, when the load of the dry-type transformer is 80% of its capacity, the transformer can operate economically, stably and reliably for a long time under the condition of natural ventilation and cooling, reaching its designed use life span. There are two types of materials for manufacturing dry-type transformers: metal materials and insulating materials. Metal materials generally can withstand higher temperatures without damage, but insulating materials will gradually lose their original mechanical properties and insulation properties and age under the action of electric field and high temperature for a long time, and will even age quickly after the temperature exceeds a certain value. According to the technical information provided by the epoxy resin dry-type transformer manufacturer, the insulation material epoxy resin is filled between each turn of the epoxy resin dry-type transformer winding. Therefore, the aging speed of the epoxy resin dry-type transformer mainly depends on Due to the aging speed of the epoxy resin of the insulating material, it can be said that the life of the transformer is the life of the insulating material in a certain sense. Since the aging speed of insulating material epoxy resin depends on the working temperature of insulating material epoxy resin, dry-type transformer users can only increase the power factor during use by taking effective cooling measures to prolong the service life of dry-type transformers , to maximize its economic benefits.

In the design and manufacture, the allowable temperature rise of dry-type transformers is an important indicator to measure the performance of dry-type transformers. The national standard "Dry-type Transformers" GB6450-1986 limits the temperature rise of dry-type transformers according to the heat resistance level. Transformers The allowable temperature rise can be divided into six grades: A, E, B, F, H, and C. The allowable temperature rise standards for each grade are shown in the table below:

Permissible temperature rise standards for each grade of dry-type transformers Insulation class A E. B f h C Maximum allowable temperature (°C) 105 120 130 155 180 220 Winding temperature rise limit (K) 60 75 80 100 125 150 Performance reference temperature (°C) 80 95 100 120 145 170

At present, the mainstream insulation grades of dry-type transformers used in China are Class F and Class H.

For the structure of epoxy resin, practice has proved that it follows Arrhenius' law (also known as the thermal life equation LOG(t)=a+b*1/T), that is, the famous "time-temperature equivalent" principle, in short One is: for a specific polymer material or structure, there is a linear relationship between the logarithm of its life time t and the reciprocal of the absolute temperature the material bears. Therefore, every time the material withstands a drop or rise in the half-difference temperature HIC of the life span, its life span will be doubled (or shortened) accordingly. Different materials have different half-difference temperature HIC according to the same diagnostic factor or the same material according to different diagnostic factors. Therefore, the data obtained from the accelerated aging process of epoxy resin at high temperature can be used to

Practice and research have shown that if the winding can maintain a temperature of 95°C continuously, the transformer can be guaranteed to have a service life of 20 years. According to the relationship between temperature and life, a so-called 8°C rule can also be derived: based on the life at the above temperature, if the winding temperature increases by 8°C, the service life of the transformer will be shortened by 1/2.

According to the 10-degree thermal life rule of the epoxy resin insulation material system, it is speculated and evaluated that when the insulation working temperature of the epoxy resin dry-type transformer is 95°C, the normal service life of the epoxy resin dry-type transformer is 20 years. The life of the resin dry-type transformer at low temperature operation, the insulation working temperature of the epoxy resin dry-type transformer is 90°C, leaving a margin of 5°C:

When the insulation working temperature of the transformer is 95°C, the service life of the transformer is 20 years;

When the insulation working temperature of the transformer is 80°C, the service life of the transformer is 40 years;

The working temperature of the transformer insulation is 70°C, and the service life of the transformer is 80 years;

The working temperature of the transformer insulation is 60°C, and the service life of the transformer is 160 years.

In practical applications, due to some unpredictable factors such as the structural form of the dry-type transformer itself, the loss level, the discreteness of materials and processing, the distribution and strength of the electric field, the effect and strength of the electromotive force, and the operating environment, etc., The actual service life of the dry-type transformer is affected by many factors. The above-mentioned transformer insulation working temperature is 60°C, and the theoretical calculation value of the transformer service life of 160 years is for reference only. The air conditioner is equipped with an air duct to cool down the dry-type transformer, which realizes the precise control of the coil temperature of the dry-type transformer with large capacity and load and large load changes. Under the ideal temperature of 45-55°C, the dry-type transformer The actual service life is calculated and evaluated according to 25-40% of 160 years, leaving sufficient safety margin, which should be reasonable, safe and reliable.

By adopting a device of the utility model that adopts an air duct type air conditioner and installing an air guide pipe to cool down the dry-type transformer, the coil temperature of the dry-type transformer with large capacity and load and large load change is accurately controlled at Under the ideal temperature of 45-55°C, the main factor affecting the service life of dry-type transformers, "temperature", becomes a secondary factor. According to the 10-degree rule of the epoxy resin insulation material system, the dry-type transformer is estimated and evaluated, and the service life of the transformer Up to 40-64 years, thus prolonging the service life of the dry-type transformer to the greatest extent.

2. Adopting a device of the utility model that adopts an air duct type air conditioner and installing an air duct to cool down the dry-type transformer can effectively improve the load capacity of the epoxy resin dry-type transformer by at least 30%.

GB/T1094.12-2013 "Guidelines for Loads of Dry-type Power Transformers" calculates the load capacity of dry-type power transformers under the condition of natural air circulation cooling. The standard points out that dry-type power transformers do not exceed the insulation The principle of how to operate under the allowable limit of thermal aging. The allowable value of insulation thermal aging is determined when the insulation is thermally damaged during the operation of the dry-type power transformer under the rated operating conditions and the external ambient temperature as the reference temperature. The design of dry-type power transformers is also designed in accordance with relevant national standards. Since the thermal aging of dry-type transformer insulation depends on the increase of transformer coil temperature, the increase of transformer coil temperature depends on the increase of current, and the increase of current depends on the increase of load. Therefore, to increase the load of dry-type transformer The fundamental way to increase capacity is to dissipate heat from the dry-type transformer coil in time, reduce the temperature, and improve the load-carrying capacity of the dry-type transformer under the premise of safety and economy.

Estimation of improving the load capacity of the dry-type transformer after the method of cooling the epoxy resin dry-type transformer by adding an air guide pipe to the air-ducted air conditioner:

(1) Model and related parameters of ducted air conditioner

Haier KFR-260EW/H730A 10P ducted air conditioner, with a cooling capacity of 26,000W, a cooling input of 10kW, and an applicable area of 110-160㎡.

(2) The epoxy resin dry-type transformer manufacturer provides the heating power curves of the SCB10-1600/10 epoxy resin dry-type transformer under different loads, as shown in Figure 7, and the SCB10-1600/10 epoxy resin dry-type transformer The approximate functional relationship between the load rate of the type transformer and the heating power:

P=12000×(η-10%)+3600

Among them, P is the heating power of the dry-type transformer at the load rate η, and the unit is Joule/second (J/s)

η is the load rate of the dry-type transformer

(3) Because 1 joule = 1 watt second, then 1 watt = 1 joule / second, that is, 1W = 1J/s

Therefore, the cooling capacity of the 10P ducted air conditioner is 26000W=26000 J/s

Assuming that the effective utilization rate of the cooling capacity of the 10P ducted air conditioner is 50%, the heat that can be replaced by the 10P ducted air conditioner per unit time (per second) is 26000 J×50%=13000 J

At the same time, it is assumed that the load rate of the epoxy resin dry-type transformer is 130%.

P=18000 J/s, that is, the calorific value per unit time (per second) at this time is 18000 J

From the above assumptions, it can be known that when the load rate of the epoxy resin dry-type transformer is 130%, and the 10P ducted air-conditioning refrigeration works at the same time and its effective utilization rate is 50%, the heat that the dry-type transformer has not been displaced is: 18000 J— 13000J=5000J

At this time, the unit time of the ducted air conditioner (per 5000 J of heat that is not displaced within seconds) is equivalent to the heat generation of the epoxy resin dry-type transformer with a load rate of 21.7%.

Generally, they are installed in the transformer cabinet and are in a closed state (GB1094.11-2007 3.4 Closed dry-type transformer refers to a transformer placed in a ventilated shell and cooled by external air circulation), so the ducted air-conditioning refrigeration produces After the cold air flows out through the transformer heat dissipation duct, it basically dissipates in the closed transformer cabinet, which reduces the temperature of the transformer working environment and is beneficial to the overall convection and radiation cooling of the dry-type transformer.

From the above analysis and calculation, it can be seen that by adopting a device for cooling dry-type transformers using air-duct air conditioners and air guide pipes of the utility model, the coil temperature of dry-type transformers can be accurately controlled at the ideal temperature when the air conditioner is forced to cool. Under the condition of 45-55℃, it is economical, efficient and safe to increase the load capacity of dry-type transformers by at least 30%.

3. The energy saving and economic benefits are prominent after adopting the device of the utility model which adopts an air duct type air conditioner and installs an air guide pipe to cool down the dry-type transformer.

(1) Effectively reduce the overall operating temperature of the dry-type transformer, reduce load loss, and have a remarkable energy-saving effect.

The load loss of a transformer increases with its operating temperature. Under the same load condition, when the operating temperature increases or decreases by 10°C, the load loss increases or decreases by about 3.93% for copper windings. This is because the load loss is directly proportional to the resistance of the winding, which increases or decreases as the temperature increases or decreases.

The following is the calculation of the reduction of load loss within 5 years of a life cycle of the ducted air conditioner after the 1600kVA dry-type transformer effectively reduces the operating temperature:

According to the accompanying technical data of the transformer, it can be known that the load loss of the dry-type transformer with the rated load is 12 kW at 120 °C, and 100 °C is selected for calculation;

After adopting a device of the utility model that adopts an air duct type air conditioner and installing an air guide pipe to cool down the dry-type transformer, the coil temperature of the dry-type transformer can be accurately controlled within the ideal temperature range of 45-55°C, and 60°C is selected for calculation. ℃, the dry-type transformer load loss can be reduced by at least:

(100℃－60℃)×3.93%/10℃×12kW=1.8864 kW

In a life cycle of the ducted air conditioner within 5 years, the working time of the air conditioner is calculated as half of the 24 hours of its own energy consumption, and the energy saved by reducing the load loss is:

1.8864 kW×12 hours/day×30 days/month×12 months/year×5 years=40746.24 kWh

Electricity expenses can be saved: 40746.24 kWh × 0.67 yuan/kwh = 27299.98 yuan

(2) Reasonably reduce the number of dry-type transformers under the condition of safety and reliability, thereby saving the basic electricity expenses of dry-type transformers, and the economic benefits are outstanding.

Case: Our company’s galvanizing workshop originally used two 1600kVA dry-type transformers. The total power of the load carried by them during safe and reliable operation is 1600×2×80%=2560kW, and the total power of all equipment in the galvanizing workshop is 2114.9 through theoretical calculations. kW, change, and power distribution designers should consider the long-term safe and stable operation of dry-type transformers on the one hand, and consider leaving a certain margin to meet the demand for later load increases on the other hand. From a design point of view, the total power of all equipment is 2114.9kW, and there is no problem with two 1600kVA dry-type transformers. However, in actual use, the load is not put into use at the same time at full power. According to statistics and data analysis, the simultaneous utilization rate of the load can only reach 70% under normal circumstances.

Here, the actual usage is calculated and compared as follows:

(a) If two 1600kVA dry-type transformers are put into operation at the same time, the load rate of the two dry-type transformers is:

2114.9kW×70%÷(1600kVA×2)×100%=46.3%

In this case, the utilization rate of the dry-type transformer is extremely low, the energy waste is serious, and it is not economical.

(b) If a 1600kVA dry-type transformer is put into operation at this time and one is out of service, the load rate of this dry-type transformer is:

2114.9kW×70%÷1600kVA×100%=92.5%

In this case, the dry-type transformer is economical and efficient. Although the coil temperature of the dry-type transformer can reach up to 95°C, it is a class H insulation epoxy resin dry-type transformer with an average temperature rise limit of 125°C. normal operating temperature.

(c) Adopting a device of the utility model that adopts an air duct type air conditioner and installing an air duct to cool down the dry-type transformer, the coil temperature of the dry-type transformer can be precisely controlled at an ideal temperature of 45-55°C during forced air cooling , calculated on the basis of a 30% increase in the load capacity of the dry-type transformer, the theoretical load rate of the dry-type transformer at this time is:

2114.9kW×70%÷【1600kVA×(1+30%)】×100%=71.2%

In this case, the use of dry-type transformers is economical, efficient and safe.

(3) Adopt a device of the utility model that adopts an air duct type air conditioner and installs an air duct to cool down the dry-type transformer, so that the coil temperature of the dry-type transformer can be precisely controlled at an ideal temperature of 45-55°C during forced air cooling Comprehensive economic benefit analysis:

(a) One-time investment cost for installing 10P ducted air conditioner: about 20,000 yuan, and the service life of ducted air conditioner is calculated as 5 years;

The average annual fixed cost expenditure for ducted air conditioners is:

20,000 yuan ÷ 5 years = 4,000 yuan/year.

(b) Related parameters of Haier KFR-260EW/H730A 10P ducted ducted air conditioner: cooling capacity 26000W; rated cooling power 10kW;

(c) The 10P ducted air conditioner is calculated according to the limit working time for 24 hours a day, and the average electricity price is 0.67 yuan per kWh

10P ducted air conditioner basic operating electricity cost per year is:

10 kW×24 hours/day×30 days/month×0.67 yuan/kWh×12 months/year=57888 yuan/year

(d) Calculation of annual no-load power consumption and electricity bill for a 1600kVA dry-type transformer (from the transformer technical data, it can be seen that the no-load loss of the dry-type transformer is 3 kW, and the transformer load loss will increase to 12 kW after the load is applied):

3 kW x 24 hours/day x 30 days/month x 12 months/year = 25920 kWh/year

The annual no-load electricity consumption of a 1600kVA dry-type transformer is:

25920 kWh × 0.67 yuan/kwh = 17366.4 yuan

(e) The annual fixed electricity fee for a 1600kVA dry-type transformer is:

1600 kVA×19 yuan/kVA .month 12 months/year=364800 yuan/year;

(f) After the ducted air conditioner is installed with an air duct to cool the dry-type transformer, the load loss of the ducted air conditioner within 5 years of a life cycle saves electricity expenses: 27299.98 yuan

Therefore, after disabling a transformer and installing a 10P ducted air conditioner, at least electricity bills can be saved every year:

364800 yuan/year+17366.4 yuan/year-4000 yuan/year-57888 yuan/year

=320278.4 yuan/year

Save money over the lifetime of a ducted air conditioner:

320278.4 yuan/year × 5 years + 27299.98 yuan = 1628691.98 yuan

According to the above data, the energy-saving effect and the economic benefit are outstanding after adopting the device of the utility model which adopts the air-duct type air conditioner and installs the air-guiding pipe to cool the dry-type transformer.

The above implementation examples have described the utility model in detail. The above is a preferred implementation example of the utility model. It should not limit the scope of the utility model. Still belong to the scope covered by the present utility model.

Claims (1)

1. A kind of 1. device to be cooled using air-duct-type air-conditioner installation guide duct to dry-type transformer, it is characterised in that the use It is to utilize cold air caused by air-duct-type air-conditioner refrigeration that air-duct-type air-conditioner, which installs the device that guide duct cools to dry-type transformer additional, Plenum chamber is connected to via pipeline to lead to below dry-type transformer heat dissipation channel by guide duct, is then dissipated via inside transformer All dissipated after hot-flow flue outflow in the transformer case of closing, the air-duct-type air-conditioner air outlet installs plenum chamber（3）, separate Six guide ducts（14、15、16、17、18、19）It is respectively communicated to three groups of coils of dry-type transformer（A phase, B phase, C phase）Radiating Passage Xia Kou positions；The cooling activation control of the air-duct-type air-conditioner is controlled by two sets of autonomous control systems：First, wind pipe type is empty The indoor environment NTC for carrying temp testing controlling system is adjusted to switchgear house or transformer station's indoor temperature detection, according to the control wind that imposes a condition The start and stop of tube-type air conditioner；Second, dry-type transformer coil temp testing controlling system coil temperature transducer PT100 is to dry type transformation Device coil temperature is detected, and according to the control auxiliary reclay that imposes a condition, is switched to simulation air-conditioning dedicated temperature sensor circuit Control the start and stop of air-duct-type air-conditioner.