Oil temperature control method of transformer and transformer using same
阅读说明：本技术 一种变压器的油温控制方法及使用该方法的变压器 (Oil temperature control method of transformer and transformer using same ) 是由 陈欢 林先明 桂灵杰 李有明 于 2019-04-19 设计创作，主要内容包括：本发明提供了一种变压器的油温控制方法及使用该方法的变压器,所述控制方法通过多个温度传感器采集到的温度信号,计算出温度检测结果趋势值,再对温度检测结果趋势值进行修正,然后根据变压器顶层油温的温度检测结果趋势值,控制变压器降温设备的运行,通过控制变压器的冷却风机和/或压缩机的运行,利用冷媒介质和蒸发器对变压器进行降温处理,将变压器的油温精确控制,使变压器在稳定的状态下工作,变压器的使用寿命也得到了提升。(The invention provides an oil temperature control method of a transformer and the transformer using the method, the control method calculates a trend value of a temperature detection result through temperature signals acquired by a plurality of temperature sensors, corrects the trend value of the temperature detection result, controls the operation of transformer cooling equipment according to the trend value of the temperature detection result of the top oil temperature of the transformer, and controls the operation of a cooling fan and/or a compressor of the transformer, and utilizes a refrigerant medium and an evaporator to cool the transformer, so that the oil temperature of the transformer is accurately controlled, the transformer works in a stable state, and the service life of the transformer is also prolonged.)
1. A method for controlling oil temperature of a transformer, the method comprising:
s1, arranging a plurality of temperature sensors in the transformer oil tank, and synchronously sending collected temperature signals to the controller by the plurality of temperature sensors;
s2, averaging the temperature signals and recording as
S3, averaging a plurality of temperature values for M times
and S4, controlling the operation of the cooling equipment of the transformer according to different control intervals in which the trend values of the temperature detection results are located.
2. The oil temperature control method of a transformer according to claim 1, further comprising, in the step S4:
s41: preferably, when the trend value T of the temperature detection result is less than or equal to 30 ℃, the cooling fan is closed, the compressor stops running, and the transformer oil cooling circulation is utilized to automatically cool;
s42: preferably, when the temperature detection result trend value is more than 30 ℃ and T is less than or equal to 55 ℃, a cooling fan of the transformer is started, and the rotating speed of the cooling fan is controlled;
s43: preferably, when the temperature detection result trend value is more than 55 ℃ and less than or equal to 70 ℃, the cooling fan stops running and the compressor is used for refrigerating;
s44: preferably, when the temperature detection result trend value is more than 70 ℃ and less than or equal to 85 ℃, the fan and the compressor are started simultaneously, the rotating speed of the cooling fan is increased to the highest rotating speed, the operating frequency of the compressor is increased to the maximum operating frequency, and the transformer oil is cooled.
3. The oil temperature control method of a transformer according to claim 2, wherein the S42 further comprises the steps of:
s421: when the temperature detection result trend value is more than 30 ℃ and less than or equal to 40 ℃, the rotating speed of the cooling fan operates at a constant speed of a first rotating speed omega 1;
s422: when the temperature detection result trend value is more than 40 ℃ and less than or equal to 55 ℃, the cooling fan operates at a second rotating speed omega 2, wherein omega 2 is omega 1+2.2e(T-30)/7。
4. The oil temperature control method of a transformer according to claim 2, wherein the S43 comprises the steps of:
s431: determining a target frequency F1 of the compressor according to the temperature detection result trend value, and controlling the compressor to perform refrigeration operation for a first preset time t1 according to the target frequency F1;
s432: detecting a variation value delta T1 of the top oil temperature of the transformer before and after T1, and if the variation value delta T1 is larger than a first preset temperature value, executing a step S433;
s433: controlling the operation frequency of the compressor to increase to a first preset frequency F2, and continuously operating for a second preset time t2, wherein the first preset frequency F2 is F1 +. DELTA.F;
s434: and detecting a change value delta T2 of the top oil temperature of the transformer before and after T2, and if the change value delta T2 is smaller than a second temperature preset value, returning to the step S431, and controlling the operation frequency of the compressor to be maintained at the frequency F1 for operation.
5. The oil temperature control method of a transformer according to claim 1, wherein in S2, the specific calculation formula of the trend value of the temperature detection result is: mtr ═ M (3) + M (1) -2 xm (2))/2+ M (3).
6. The oil temperature control method of a transformer according to claim 1, wherein in S3, the temperature detection result trend value is corrected by using the following formula:
formula 1): t1 ═ Ti-0.12 × Ts;
equation 2): t2 ═ Ti +0.08 × Ts;
equation 3): t3 ═ Ti-0.1 × Ts;
wherein Ti is a temperature detection result trend value; when the outdoor temperature Ts temperature range is: ts is more than or equal to 40 ℃ and less than or equal to 0 ℃, and the corrected temperature detection result trend value T1 is corrected and calculated by adopting a formula 1;
when the outdoor temperature Ts temperature range is: ts is more than or equal to 0 ℃ and less than or equal to 25 ℃, and the corrected temperature detection result trend value T2 is corrected and calculated by adopting a formula 2;
when the outdoor temperature Ts temperature range is: ts is more than or equal to 25 ℃ and less than or equal to 45 ℃, and the corrected temperature detection result trend value T3 is corrected and calculated by adopting a formula 3.
7. The oil temperature control method of a transformer according to claim 7, wherein the temperature correction formula further includes a second correction: and (3) after the second correction, the trend value T4 of the temperature detection result is T1+ delta T, or T4 is T2+ delta T, and T4 is T3+ delta T, when the transformer is in a power utilization peak period, the delta T is a positive value, and when the power utilization is in a stationary period, the delta T is a negative value.
8. The oil temperature control method of a transformer according to claim 1, wherein the S4 further comprises the steps of:
s5, detecting the top oil temperature of the transformer in real time, and when the temperature is abnormal for multiple times within a third preset time t3, entering an alert area by the transformer and executing the step S6;
and S6, calculating the maximum hot point temperature value of the transformer winding according to the environment temperature, the equivalent load current and the duration, and judging whether the transformer is cut off from the power grid.
9. A transformer, characterized in that the transformer employs the oil temperature control method of the transformer according to any one of claims 1 to 9.
Technical Field
The invention relates to the field of transformers, in particular to a transformer oil temperature control method and a transformer using the same.
Background
At present, the transformer is an important and indispensable power device in a power transmission grid and plays a vital role in regulating the voltage of the grid. Power transformers suffer from core and winding losses during use, which leads to increased core and winding temperatures. In order to ensure safe and reliable operation of the transformer, the winding temperature, the core temperature and the transformer oil temperature of the transformer need to be limited within a safe range, so the transformer needs to be cooled. At present, most transformers running on a power grid are still transformers, a common transformer cools transformer oil inside the transformer by means of radiating fins arranged around the transformer, but the radiating fins are greatly influenced by the environment and often cannot achieve the expected effect when the environment temperature is high, so that the transformer has large faults, for example, the insulation performance of the transformer oil is reduced, coils are aged and even the transformer is ignited and exploded due to overhigh oil temperature.
The temperature rise standard of the transformer in China is subject to the ambient temperature of 40 ℃, so the top oil temperature of the transformer generally cannot exceed 40 ℃ plus 55 ℃ to 95 ℃. The temperature of the top oil exceeds 95 deg.C, and the temperature of the inner coil exceeds the heat-resisting strength of the coil insulator, so that the insulation will not age too fast, and the monitoring of the temperature of the top oil of the transformer should be controlled below 85 deg.C. In the range of 80-140 ℃, the service life loss of the paper insulation of the transformer is doubled every 6 ℃ rise of the temperature. This rule is commonly referred to as the six degree rule. When the cooling equipment is out of order, the cooling condition is destroyed, the running temperature of the transformer rises rapidly, and the life loss of the transformer insulation is increased rapidly. As described in the literature, the insulating material can be used for 20 years when the temperature is kept at 95 ℃; the temperature is 105 ℃, the service life is about 7 years, and the temperature is 120 ℃ for about 2 years; the temperature is 170 ℃ for about 10-12 days.
In order to reduce waste, improve the electric energy quality, improve the working efficiency and the service life of the transformer, reduce the temperature of transformer cooling oil and improve the transformer oil cooling technology, the technology becomes a preferred technology for breaking through various bottlenecks.
Disclosure of Invention
The invention aims to provide a transformer oil temperature control method and a transformer using the method, which are used for cooling through a cooling fan and a compressor, accurately controlling the oil temperature of the transformer together and ensuring that the transformer works and operates in a proper temperature range.
In order to achieve the purpose, the technical scheme of the invention is realized as follows:
a method of controlling an oil temperature of a transformer, the method comprising the steps of:
s1, arranging a plurality of temperature sensors in the transformer oil tank, and synchronously sending collected temperature signals to the controller by the plurality of temperature sensors;
s2, averaging the temperature signals and recording asRecording the average temperature value M times within a preset time Ty
S3, averaging a plurality of temperature values for M times
and S4, controlling the operation of the cooling equipment of the transformer according to different control intervals in which the trend values of the temperature detection results are located.
Further, the step S4 includes the following steps:
s41: when the trend value T of the temperature detection result is less than or equal to 30 ℃, the cooling fan is closed, the compressor stops running, and the temperature is automatically reduced by using the oil cooling circulation of the transformer;
s42: when the temperature detection result trend value is more than 30 ℃ and T is less than or equal to 55 ℃, starting a cooling fan of the transformer and simultaneously controlling the rotating speed of the cooling fan;
s43: when the temperature detection result trend value is more than 55 ℃ and less than or equal to 70 ℃, the cooling fan stops running and the compressor is used for refrigerating;
s44: and when the temperature detection result trend value is more than 70 ℃ and less than or equal to 85 ℃, simultaneously starting the fan and the compressor, increasing the rotating speed of the cooling fan to the highest rotating speed, increasing the operating frequency of the compressor to the maximum operating frequency, and cooling the transformer oil.
Further, the S42 further includes the following steps:
s421: when the temperature detection result trend value is more than 30 ℃ and less than or equal to 40 ℃, the rotating speed of the cooling fan operates at a constant speed of a first rotating speed omega 1;
s422: when the temperature detection result trend value is more than 40 ℃ and less than or equal to 55 ℃, the cooling fan operates at a second rotating speed omega 2, wherein omega 2 is omega 1+2.2e(T-30)/7。
Further, the S43 includes the following steps:
s431: determining a target frequency F1 of the compressor according to the temperature detection result trend value, and controlling the compressor to perform refrigeration operation for a first preset time t1 according to the target frequency F1;
s432: detecting a variation value delta T1 of the top oil temperature of the transformer before and after T1, and if the variation value delta T1 is larger than a first preset temperature value, executing a step S433;
s433: controlling the operation frequency of the compressor to increase to a first preset frequency F2, and continuously operating for a second preset time t2, wherein the first preset frequency F2 is F1 +. DELTA.F;
s434: and detecting a change value delta T2 of the top oil temperature of the transformer before and after T2, and if the change value delta T2 is smaller than a second temperature preset value, returning to the step S431, and controlling the operation frequency of the compressor to be maintained at the frequency F1 for operation.
Further, a specific calculation formula of the temperature detection result trend value is as follows: mtr ═ M (3) + M (1) -2 xm (2))/2+ M (3).
Further, in S3, the following formula is used for the temperature correction:
formula 1): t1 ═ Ti-0.12 × Ts;
equation 2): t2 ═ Ti +0.08 × Ts;
equation 3): t3 ═ Ti-0.1 × Ts;
wherein Ti is a temperature detection result trend value; when the outdoor temperature Ts temperature range is: ts is more than or equal to 40 ℃ and less than or equal to 0 ℃, and the corrected temperature detection result trend value T1 is corrected and calculated by adopting a formula 1;
when the outdoor temperature Ts temperature range is: ts is more than or equal to 0 ℃ and less than or equal to 25 ℃, and the corrected temperature detection result trend value T2 is corrected and calculated by adopting a formula 2;
when the outdoor temperature Ts temperature range is: ts is more than or equal to 25 ℃ and less than or equal to 45 ℃, and the corrected temperature detection result trend value T3 is corrected and calculated by adopting a formula 3.
Further, the temperature correction formula further comprises a second correction: and (3) after the second correction, the trend value T4 of the temperature detection result is T1+ delta T, or T4 is T2+ delta T, and T4 is T3+ delta T, when the transformer is in a power utilization peak period, the delta T is a positive value, and when the power utilization is in a stationary period, the delta T is a negative value.
Further, the S4 further includes the following steps:
s5, detecting the top oil temperature of the transformer in real time, and when the temperature is abnormal for multiple times within a third preset time t3, entering an alert area by the transformer and executing the step S6;
and S6, calculating the maximum hot point temperature value of the transformer winding according to the environment temperature, the equivalent load current and the duration, and judging whether the transformer is cut off from the power grid.
The invention also provides a transformer, and the transformer adopts the oil temperature control method of the transformer.
Compared with the prior art, the oil temperature control method of the transformer has the following advantages:
1, a natural oil circulating cooling structure of a traditional transformer is changed, the control precision of the transformer oil temperature is improved, the heat dissipation cooling efficiency of the transformer can be improved, the service life of the transformer can be prolonged, and accidents can be reduced;
2, the compressor and the cooling fan in the transformer are adjusted in different modes, the control modes are flexible and various, the temperature of the transformer can be accurately controlled according to the trend value of the temperature detection result, the cooling effect is good, and the method is suitable for various complex occasions and environments; the energy waste and noise pollution caused by the fact that the rotating speed of the cooling fan keeps a high-speed rotating state in the prior art are avoided.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate an embodiment of the invention and, together with the description, serve to explain the invention and not to limit the invention. In the drawings:
fig. 1 is a schematic flow chart of a method for controlling an oil temperature of a transformer according to the present invention;
FIG. 2 is a schematic flow chart of the present invention for controlling the cooling fan and the compressor;
fig. 3 is a schematic control flow diagram of the compressor of the present invention.
Detailed Description
It should be noted that the embodiments and features of the embodiments may be combined with each other without conflict.
Reference will now be made in detail to the exemplary embodiments, examples of which are illustrated in the accompanying drawings. When the following description refers to the accompanying drawings, like numbers in different drawings represent the same or similar elements unless otherwise indicated. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present invention. Rather, they are merely examples of apparatus and methods consistent with certain aspects of the present invention.
The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used in this specification and the appended claims, the singular forms "a", "an", and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It should also be understood that the term "and or" as used herein refers to and encompasses any and all possible combinations of one or more of the associated listed items.
It is to be understood that although the terms first, second, third, etc. may be used herein to describe various information, these information should not be limited to these terms. These terms are only used to distinguish one type of information from another. For example, first information may also be referred to as second information, and similarly, second information may also be referred to as first information, without departing from the scope of the present invention. The word "if" as used herein may be interpreted as "at … …" or "when … …" or "in response to a determination", depending on the context.
The present invention will be described in detail below with reference to the embodiments with reference to the attached drawings.