CN103324130A - Intelligent air-cooling frequency-changing energy-saving system and method of transformer - Google Patents

Abstract

The intelligent frequency conversion air-cooled energy-saving method and system for transformers described in the present invention jointly control the operating number of cooler groups and the speed of fans according to the top layer oil temperature, winding temperature and load current of the transformer, and use the transformer top layer oil temperature and winding temperature as the frequency converter Frequency modulation control parameters, taking into account the change of load current to control the cooler speed and the input cut-off of the cooler group. The above-mentioned intelligent frequency conversion air-cooling energy-saving method for transformers effectively avoids the poor flexibility, single operation mode, low control precision, and large noise in the existing technology of transformer air-cooling and frequency conversion energy-saving methods. But the result is not good, it cannot be economically applied to various complex occasions and environments, and the economical operation of the cooler cannot be realized, resulting in the problem of waste of resources.

Description

An intelligent air-cooled frequency conversion energy-saving system and method for transformers

technical field

The invention relates to a transformer air cooling system, which belongs to the technical field of power equipment. the

Background technique

The power transformer is one of the main equipment in the power system. Its main functions are voltage conversion and current transmission. The no-load loss, load loss and ambient temperature will all affect the temperature of the transformer cooling oil. The greater the change in the transformer load, the greater the loss. The greater the temperature change, the greater the temperature of the transformer is also affected by the external environment. Even on the same day, due to the superposition of day and night temperature changes and load peak-to-valley differences, it is one of the main reasons for the large temperature changes of the transformer, which in turn affects The long-term stable operation and service life of the transformer are ensured. the

The traditional transformer cooling system adopts the relay control mode, and the coil of the AC contactor is driven by the opening and closing of the limited mechanical contacts of the temperature controller (oil layer surface, winding temperature gauge), so as to connect the working circuit of the cooler, and use a thermal relay Realize overload and lack of phase protection, and use circuit breakers to realize short-circuit protection. This mode has defects such as complex circuits, large volume, and high device failure rate. The conventional temperature control node is small, the capacity is small, and the error is large. The AC of the working circuit of the control cooler The contactor starts frequently, and the contacts are easy to burn out, resulting in poor contact or sticking together, which becomes a non-negligible factor for the motor to lose phase or damage the insulation. On the other hand, the combination of circuit breaker, contactor and thermal relay is a series of problems such as the bulk of the control cabinet, the increase of manufacturing and transportation costs, the increase of maintenance workload, and the source of income when replacing. the

Modern transformer cooling systems adopt intelligent control, generally controlled by microprocessors or programmable logic controllers. Although they are intelligent and have functions such as fault query and network monitoring operations, there are still many shortcomings: single operation mode, not economical It is suitable for various complicated occasions and environments; it cannot realize the economical operation of the cooler, and also causes a waste of resources; the control circuit is complex, and it cannot continuously and accurately track the oil temperature and load operation of the transformer; the starting current Large, the impact on the power grid is relatively large, because the contactor is prone to aging; the temperature control is not accurate, and when a group of contacts of the thermometer burn out, the system cannot operate normally; the temperature load needs to provide more nodes, which is the cable The number of cores increases, the cost of maintenance and transformation is high, and the difficulty of construction increases. the

Patent document CN202404420U discloses an intelligent frequency conversion air-cooled control device for power transformers, including a transformer temperature acquisition module, a transformer load acquisition module, a programmable controller, a frequency converter, a touch display, and two sets of cooling fans. The current directly participates in the frequency conversion control, and the speed of the cooling fan is controlled by the magnitude of the load current; when the oil temperature reaches 55-60°C, the two sets of cooling fans are in the frequency conversion operation state on time; when the oil temperature of the transformer drops to 45°C When the temperature falls below, the two groups of cooling fans stop working, and the transformer is in a self-cooling state; when the oil temperature of the transformer rises to 65°C, the two groups of fans are put into operation at the same time, and they will switch to power frequency mode after continuous operation for 1 hour; when the oil temperature of the transformer When the temperature rises to 70°C, the two sets of cooling fans switch from power frequency to variable frequency mode; when the oil temperature of the transformer exceeds 75°C, the two sets of cooling fans operate in overfrequency (60Hz) mode; when the temperature drops to 65°C, the two sets of cooling fans The cooling fans of the group are converted to the mode of variable frequency and timed circulation. This technical solution controls the operation of the inverter according to the magnitude of the load current to adjust the speed of the cooling fan. The purpose of cooling is to reduce the temperature. The oil temperature of the transformer is the most important parameter. In addition, it is also affected by the external ambient temperature. When the external ambient temperature is very low, the oil temperature of the transformer will not be too high. At this time, the speed of the fan is still controlled by the load current, and it cannot be accurately tracked according to the change of the transformer oil temperature. Cooling control, while the cooling fan is still in a state of high-speed rotation, which invisibly causes waste of energy and increases noise, causing inconvenience to surrounding residents and staff. In addition, this technical solution only has two sets of cooling fans, which has limited cooling effect, poor flexibility, single operation mode, and cannot be economically applied to various complex occasions and environments; the economical operation of the cooler cannot be realized, and resources waste. the

Contents of the invention

The technical problem to be solved by the present invention is that the air-cooled frequency conversion energy-saving method for transformers in the prior art has poor flexibility, single operation mode, and low control precision. It is economical and suitable for various complex occasions and environments, and cannot realize the economical operation of the cooler, resulting in a waste of resources, thereby providing a method and system for energy-saving transformer intelligent frequency conversion air cooling with high control precision. the

In order to solve the problems of the technologies described above, the present invention is achieved through the following technical solutions:

An intelligent variable frequency air-cooled energy-saving method for transformers. According to the top layer oil temperature, winding temperature and load current of the transformer, the number of coolers running and the fan speed are jointly controlled:

(1) When the oil temperature on the top layer of the transformer or the winding temperature T≤30°C and the load current is less than 70% of the rated current, the working cooler group is started, and the maximum frequency of the frequency converter of the working cooler group is limited to f _1max , and the The initial frequency of the frequency converter of the working cooler group is f ₁ , and the frequency converter of the working cooler group operates at the initial frequency f ₁ at a constant frequency and constant speed;

(2) When the oil temperature on the top layer of the transformer or the winding temperature is 30℃<T≤50℃,

At this time, when the oil temperature on the top layer of the transformer or the temperature of the winding changes by 1°C, the frequency of the working cooler group changes by Vf ₂ ,

The inverter frequency of the working cooler group is set to f ₂ ,

f ₂ =f ₁ +(T-30)×Vf ₂ ;

(3) When the oil temperature on the top layer of the transformer or the winding temperature is 50℃<T≤65℃ or the load current is greater than 70% of the rated current, the frequency converter of the working cooler group is at the highest frequency f _1max and the auxiliary cooler is automatically put into operation group, the highest frequency of the frequency converter of the auxiliary cooler group is set to f _2max , the initial frequency of the frequency converter of the auxiliary cooler group is f′ ₃ ,

At this time, when the temperature of the oil on the top layer of the transformer or the temperature of the winding changes by 1°C, the frequency of the frequency converter of the auxiliary cooler group changes by Vf ₃ ,

The frequency converter frequency of the auxiliary cooling group is set to f ₃ ,

f ₃ =f' ₃ +(T-50)×Vf ₃ ;

(4) When the oil temperature on the top layer of the transformer or the winding temperature T≤47℃ and the load is less than 70%, the auxiliary cooler group is automatically cut off;

(5) When the oil temperature on the top layer of the transformer or the winding temperature is 65°C<T≤70°C, the frequency converter of the working cooler group is set to the highest frequency f _1max , and the highest frequency of the frequency converter of the auxiliary cooler group is set to f _2max , the standby cooler group is automatically put into operation, the highest frequency of the frequency converter of the standby cooler group is set to f _3max , the initial frequency of the frequency converter of the standby cooler group is set to f′ ₄ ,

At this time, Vf ₄ changes for every 1°C change in frequency,

The inverter frequency of the spare cooler group is set to f ₄ ,

f ₄ =f' ₄ +(T-65)×Vf ₄ ;

(6) When the oil temperature on the top layer of the transformer or the winding temperature T≤63°C, the spare cooler group is automatically cut off;

(7) When the oil temperature on the top layer of the transformer or the winding temperature T≥70°C, the transformer will stop running. the

The initial frequency of the frequency converter of the working cooler is _{5Hz≤f1≤10Hz} .

The initial frequency f ₁ of the frequency converter of the working cooler is 5 Hz.

The initial frequency of the frequency converter of the auxiliary cooler is 30Hz≤f′ ₃ ≤40Hz.

The initial frequency f' ₃ of the frequency converter of the auxiliary cooler is 36Hz.

The initial frequency of the frequency converter of the standby cooler is 35Hz≤f′ ₄ ≤45Hz.

The initial frequency f′ ₄ of the frequency converter of the standby cooler is 40Hz.

The highest frequency f _1max of the frequency converter of the working cooler is 48 Hz.

The maximum frequency f _2max of the frequency converter of the auxiliary cooler is 58.5Hz.

The maximum frequency f _3max of the frequency converter of the standby cooler is 60Hz.

An intelligent frequency conversion air-cooled energy-saving system for transformers includes a detection feedback unit, a programmable logic controller, a work instruction unit, an operation unit, a frequency converter, a remote control unit, a power supply unit and a cooler group. the

The programmable logic controller adopts the transformer intelligent frequency conversion air cooling energy-saving method to control the operation of the cooler. the

The cooler group is divided into working cooler group, auxiliary cooler group and spare cooler group:

The working cooler group includes three groups of coolers;

The auxiliary cooler group includes a group of coolers;

The standby cooler group includes a group of coolers;

Each cooler is equipped with a frequency converter. the

The power supply unit includes two main power supplies that are independent and mutually backup. When one main power supply fails, the other main power supply will be put into use, and an alarm signal will be sent, and the failure signal will be sent to the control center through the remote control unit . the

Above-mentioned technical scheme of the present invention has the following advantages compared with prior art:

The intelligent frequency conversion air-cooled energy-saving method for transformers described in the present invention controls the running number of coolers and fan speed jointly according to the top layer oil temperature, winding temperature and load current of the transformer, and takes the top layer oil temperature and winding temperature of the transformer as frequency modulation control parameters of the inverter , taking into account the change of load current to control the cooler speed and the input cut-off of the cooler group. The above-mentioned intelligent frequency conversion air-cooling energy-saving method for transformers effectively avoids the poor flexibility, single operation mode, and low control precision of the prior art transformer air-cooling variable-frequency energy-saving methods. There is no precise tracking control based on transformer oil temperature and winding temperature changes, and the cooling effect is not effective. Well, it cannot be economically applied to various complex occasions and environments, and the economical operation of the cooler cannot be realized, resulting in a waste of resources. the

Description of drawings

In order to make the content of the present invention more easily understood clearly, below in conjunction with accompanying drawing, the present invention is described in further detail, wherein,

Fig. 1 is the flowchart of transformer intelligent frequency conversion air-cooled energy-saving method of the present invention;

Fig. 2 is a block diagram of the transformer intelligent frequency conversion air-cooled energy-saving system according to the present invention. the

The reference signs in the figure are represented as: 1-transformer, 2-detection feedback unit, 3-programmable controller, 4-status display unit, 5-operation unit, 6-frequency converter, 7-cooler group, 8-remote Control unit, 9 - Power supply unit. the

Detailed ways

Example 1:

The flow chart 1 of an intelligent variable-frequency air-cooled energy-saving method for transformers provided in this embodiment is shown in flow chart 1. The intelligent variable-frequency air-cooled energy-saving method for transformers is to jointly control the cooler according to the top layer oil temperature, winding temperature and load current of the transformer. Number of runs and fan speeds, the method is as follows:

(1) When the oil temperature on the top layer of the transformer or the winding temperature T≤30°C and the load current is less than 70% of the rated current, the working cooler group is started, and the maximum frequency of the frequency converter of the working cooler group is limited to f _1max , and the The initial frequency of the frequency converter of the working cooler group is f ₁ , and the frequency converter of the working cooler group operates at the initial frequency f ₁ at a constant frequency and constant speed.

The initial frequency of the frequency converter of the working cooler is _{5Hz≤f1≤10Hz} .

In this implementation, the initial frequency f ₁ of the frequency converter of the working cooler is 5 Hz.

In other embodiments, the initial frequency f ₁ may take values such as 6 Hz, 7 Hz, 8 Hz, 9 Hz, 10 Hz, etc., which are selected according to the type, working condition and working environment of the transformer.

(2) When the oil temperature on the top layer of the transformer or the winding temperature is 30℃<T≤50℃,

At this time, when the oil temperature on the top layer of the transformer or the temperature of the winding changes by 1°C, the frequency of the working cooler group changes by Vf ₂ ,

The inverter frequency of the working cooler group is set to f ₂ ,

f ₂ =f ₁ +(T-30)×Vf ₂ .

The maximum frequency of the frequency converter of the working cooler is limited to f _1max =48Hz.

(3) When the oil temperature on the top layer of the transformer or the winding temperature is 50℃<T≤65℃ or the load current is greater than 70% of the rated current, the frequency converter of the working cooler group is at the highest frequency f _1max and the auxiliary cooler is automatically put into operation group, the highest frequency of the frequency converter of the auxiliary cooler group is set to f _2max , the initial frequency of the frequency converter of the auxiliary cooler group is f′ ₃ ,

At this time, when the temperature of the oil on the top layer of the transformer or the temperature of the winding changes by 1°C, the frequency of the frequency converter of the auxiliary cooler group changes by Vf ₃ ,

The frequency converter frequency of the auxiliary cooling group is set to f ₃ ,

f ₃ =f' ₃ +(T-50)×Vf ₃ .

The initial frequency of the frequency converter of the auxiliary cooler is 30Hz≤f′ ₃ ≤40Hz.

In this embodiment, the initial frequency f' ₃ of the frequency converter of the auxiliary cooler is 36 Hz.

In other embodiments, the initial frequency _f'3 of the frequency converter of the auxiliary cooler can be selected from 30 Hz, 32 Hz, 36 Hz, 38 Hz, 40 Hz, etc., according to the type, working condition and working environment of the transformer.

The maximum frequency f _2max of the frequency converter of the auxiliary cooler is 58.5Hz.

(4) When the oil temperature at the top of the transformer or the winding temperature T≤47°C and the load is less than 70%, the auxiliary cooler group is automatically cut off. the

(5) When the oil temperature on the top layer of the transformer or the winding temperature is 65°C<T≤70°C, the frequency converter of the working cooler group is at the highest frequency f _1max , and the frequency converter of the auxiliary cooler group is at the highest frequency f _2max , Automatically put into operation the spare cooler group, the maximum frequency of the inverter of the spare cooler group is limited to f _3max , the initial frequency of the inverter of the spare cooler group is set to f′ ₄ ,

At this time, Vf ₄ changes for every 1°C change in frequency,

The inverter frequency of the spare cooler group is set to f ₄ ,

f ₄ =f' ₄ +(T-65)×Vf ₄ .

The initial frequency of the frequency converter of the standby cooler is 35Hz≤f′ ₄ ≤45Hz.

In this implementation, the initial frequency f′ ₄ of the frequency converter of the standby cooler is 40 Hz.

In other embodiments, the initial frequency _f'4 of the frequency converter of the auxiliary cooler can be selected from 35Hz, 37Hz, 39Hz, 41Hz, 43Hz, 45Hz, etc., according to the type, working condition and working environment of the transformer.

The maximum frequency f _3max of the frequency converter of the standby cooler is 60Hz.

(6) When the oil temperature on the top layer of the transformer or the winding temperature T≤63°C, the spare cooler group is automatically cut off;

(7) When the oil temperature on the top layer of the transformer or the winding temperature T≥70°C, the transformer will stop running. the

This implementation also provides a transformer intelligent frequency conversion air-cooled energy-saving system, as shown in Figure 2, including a detection feedback unit 2, a programmable logic controller 3, a work instruction unit 4, an operation unit 5, a frequency converter group 6, and a remote control unit 8. Power supply unit 9 and cooler group 7. the

The programmable logic controller adopts the transformer intelligent frequency conversion air cooling energy-saving method to control the operation of the cooler. the

The cooler group 7 is divided into a working cooler group, an auxiliary cooler group and a standby cooler group. the

The working cooler group includes three groups of coolers. the

The auxiliary cooler group includes a group of coolers. the

The backup set of coolers includes a set of coolers. the

Each cooler is equipped with a frequency converter. the

The detection and feedback unit 2 detects the oil temperature at the top of the transformer, the winding temperature and the load current, and transmits the detected temperature change signal to the programmable logic controller 3 . the

The power supply unit 9 includes two independent main power supplies that are mutually standby. When one main power supply fails, the other main power supply will be put into use, and an alarm signal will be sent, and the failure signal will be sent to the remote control unit 8 at the same time. control center. The two independent main power supplies of the power supply unit 9 are 380Vac three-phase power, and the programmable logic controller 3 controls the frequency converter group 6 to convert the electric energy into the required frequency and directly supply the power to the Cooler group 7 supplies power, and at the same time takes a certain phase of electricity, that is, single-phase electricity 220Vac, to supply power to the programmable logic controller 3, the work instruction unit 4, and the operation unit 5. the

Example 2:

The flow chart 1 of an intelligent variable-frequency air-cooled energy-saving method for transformers provided in this embodiment is shown in flow chart 1. The intelligent variable-frequency air-cooled energy-saving method for transformers is to jointly control the cooler according to the top layer oil temperature, winding temperature and load current of the transformer. Number of runs and fan speeds, the method is as follows:

(1) When the oil temperature on the top layer of the transformer or the winding temperature T≤30°C and the load current is less than 70% of the rated current, start the working cooler group, the maximum frequency of the frequency converter of the working cooler group is limited to 48Hz, and the working The inverter frequency of the cooler group is 5Hz, running at constant frequency and constant speed. the

(2) When the oil temperature on the top layer of the transformer or the winding temperature is 30℃<T≤50℃,

At this time, when the oil temperature on the top layer of the transformer or the temperature of the winding changes by 1°C, the frequency of the working cooler group changes by Vf ₂ ,

That is, every time the temperature T rises by 1°C, the frequency increases by 2.15Hz, every time the oil temperature drops by 1°C, the frequency decreases by 2.15Hz, and the frequency converter of the working cooler group is set to f ₂ ,

f ₂ =f ₁ +(T-30)×Vf ₂ =[5+(T-30)×Vf ₂ ]Hz.

(3) When the oil temperature on the top layer of the transformer or the winding temperature is 50°C<T≤65°C or the load current is greater than 70% of the rated current, the frequency converter of the working cooler group is at the highest frequency of 48Hz, and the auxiliary cooler group is automatically put into operation , the highest frequency of the frequency converter of the auxiliary cooler group is set to 58.5Hz, the initial frequency of the frequency converter of the auxiliary cooler group is 36Hz,

At this time, Vf ₃ changes for every 1°C change in frequency,

That is, every time the temperature T rises by 1°C, the frequency increases by 1.5Hz, every time the oil temperature drops by 1°C, the frequency decreases by 1.5Hz, and the frequency converter of the auxiliary cooling group is set to f ₃ ,

f ₃ =f' ₃ +(T-50)×Vf ₃ =[36+(T-50)×1.5]Hz.

(4) When the oil temperature at the top of the transformer or the winding temperature T≤47°C and the load is less than 70%, the auxiliary cooler group is automatically cut off. the

(5) When the oil temperature on the top layer of the transformer or the winding temperature is 65°C<T≤70°C, the frequency converter of the working cooler group has a maximum frequency of 48Hz, and the frequency converter of the auxiliary cooler group has a maximum frequency of 58.5Hz, automatically The spare cooler group is put into operation, the highest frequency of the inverter of the spare cooler group is set to 60Hz, and the initial frequency of the inverter of the spare cooler group is set to 40Hz,

At this time, Vf ₄ changes for every 1°C change in frequency,

The inverter frequency of the spare cooler group is set to f ₄ ,

f ₄ =f' ₄ +(T-65)×Vf ₄ =[40+(T-65)×4] Hz.

(6) When the oil temperature on the top layer of the transformer or the winding temperature T≤63°C, the spare cooler group will be cut off automatically. the

(7) When the oil temperature on the top layer of the transformer or the winding temperature T≥70°C, the transformer will stop running. the

This implementation also provides a transformer intelligent frequency conversion air-cooled energy-saving system, as shown in Figure 2, including a detection feedback unit 2, a programmable logic controller 3, a work instruction unit 4, an operation unit 5, a frequency converter group 6, and a remote control unit 8. Power supply unit 9 and cooler group 7. the

The programmable logic controller adopts the transformer intelligent frequency conversion air cooling energy-saving method to control the operation of the cooler. the

The cooler group 7 is divided into a working cooler group, an auxiliary cooler group and a standby cooler group. the

The working cooler group includes three groups of coolers. the

The auxiliary cooler group includes a group of coolers. the

The backup set of coolers includes a set of coolers. the

Each cooler is equipped with a frequency converter. the

The detection and feedback unit 2 detects the oil temperature at the top of the transformer, the winding temperature and the load current, and transmits the detected temperature change signal to the programmable logic controller 3 . the

The power supply unit 9 includes two independent main power supplies that are mutually standby. When one main power supply fails, the other main power supply will be put into use, and an alarm signal will be sent, and the failure signal will be sent to the remote control unit 8 at the same time. control center. The two independent main power supplies of the power supply unit 9 are 380Vac three-phase power, and the programmable logic controller 3 controls the frequency converter group 6 to convert the electric energy into the required frequency and directly supply the power to the Cooler group 7 supplies power, and at the same time takes a certain phase of electricity, that is, single-phase electricity 220Vac, to supply power to the programmable logic controller 3, the work instruction unit 4, and the operation unit 5. the

Apparently, the above-mentioned embodiments are only examples for clear description, rather than limiting the implementation. For those of ordinary skill in the art, on the basis of the above description, other changes or changes in different forms can also be made. It is not necessary and impossible to exhaustively list all the implementation manners here. And the obvious changes or changes derived therefrom are still within the scope of protection of the present invention. the

Claims (10)

1. intelligent transformer frequency conversion air-cooled power-economizing method, top-oil temperature, winding temperature and load current co-controlling refrigeratory operation quantity and rotation speed of fan according to transformer is characterized in that:

(1) when transformer top-oil temperature or winding temperature T≤30 ℃ and load current less than rated current 70% the time, the cooler package that starts to work, the frequency converter highest frequency of described work cooler package is defined as f _1max, the frequency converter original frequency of described work cooler package is f ₁, this moment, the frequency converter of described work cooler package operated in original frequency f ₁, the constant frequency constant-speed operation;

(2) when transformer top-oil temperature or 30 ℃＜T of winding temperature≤50 ℃,

At this moment, 1 ℃ of the every variation of transformer top-oil temperature or winding temperature, described work cooler package frequency change Vf ₂,

The frequency of the frequency converter of described work cooler package is f at this moment ₂,

f ₂＝f ₁+(T-30)×Vf ₂；

(3) when transformer top-oil temperature or 50 ℃＜T of winding temperature≤65 ℃ or load current greater than rated current 70% the time, the frequency converter of described work cooler package is highest frequency f _1max, the auxiliary cooler group that automatically puts into operation, the frequency converter highest frequency of described auxiliary cooler group is set as f _2max, the frequency converter initial frequency of described auxiliary cooler group is f ' ₃,

At this moment, 1 ℃ of the every variation of described transformer top-oil temperature or winding temperature, the frequency change Vf of the frequency converter of described auxiliary cooler group ₃,

The frequency of the frequency converter of described auxiliary cooling group is f at this moment ₃,

f ₃＝f′ ₃+(T-50)×Vf ₃；

(4) when transformer top-oil temperature or winding temperature T≤47 ℃ and load less than 70% the time, the auxiliary cooler group is excised automatically;

(5) when transformer top-oil temperature or 65 ℃＜T of winding temperature≤70 ℃, the frequency converter of described work cooler package is highest frequency f _1max, the frequency converter of described auxiliary cooler group is highest frequency f _2max, the cooler package for subsequent use that automatically puts into operation, the frequency converter highest frequency of described cooler package for subsequent use is set as f _3max, the frequency converter original frequency of described cooler package for subsequent use is set as f ' ₄,

At this moment, 1 ℃ of the every variation of described transformer top-oil temperature or winding temperature, the frequency change Vf of the frequency converter of described cooler package for subsequent use ₄,

This moment, the frequency converter frequency of described cooler package for subsequent use was set to f ₄,

f ₄＝f′ ₄+(T-65)×Vf ₄；

(6) when transformer top-oil temperature or winding temperature T≤63 ℃, cooler package for subsequent use is excised automatically;

(7) when transformer top-oil temperature or winding temperature T 〉=70 ℃, this transformer is out of service, sends simultaneously alerting signal.

2. intelligent transformer frequency conversion air-cooled power-economizing method according to claim 1 is characterized in that: the frequency converter original frequency 5Hz≤f of described work refrigeratory ₁≤ 10Hz.

3. intelligent transformer frequency conversion air-cooled power-economizing method according to claim 1 and 2 is characterized in that, the frequency converter original frequency f of described work refrigeratory ₁=5Hz.

4. intelligent transformer frequency conversion air-cooled power-economizing method according to claim 1 is characterized in that: the frequency converter original frequency 30Hz≤f ' of described auxiliary cooler ₃≤ 40Hz.

5. according to claim 1 or 4 described intelligent transformer frequency conversion air-cooled power-economizing methods, it is characterized in that the frequency converter original frequency f ' of described auxiliary cooler ₃=36Hz.

6. intelligent transformer frequency conversion air-cooled power-economizing method according to claim 1 is characterized in that, the frequency converter original frequency 35Hz≤f ' of described refrigeratory for subsequent use ₄≤ 45Hz.

7. it is characterized in that: the frequency converter original frequency f ' of described refrigeratory for subsequent use according to claim 1 or 6 described intelligent transformer frequency conversion air-cooled power-economizing methods, ₄=40Hz.

8. intelligent transformer frequency conversion air-cooled power-economizing method according to claim 1 is characterized in that: the frequency converter highest frequency f of described work refrigeratory _1max=48Hz;

The frequency converter highest frequency f of described auxiliary cooler _2max=58.5Hz;

The frequency converter highest frequency f of described refrigeratory for subsequent use _3max=60Hz.

9. an intelligent transformer frequency conversion air-cooled energy conserving system comprises and detects feedback unit, programmable logic controller (PLC), work indicating member, operating unit, frequency converter, remote control unit, power supply unit and cooler package, it is characterized in that:

Described programmable logic controller (PLC) adopts intelligent transformer frequency conversion air-cooled power-economizing method claimed in claim 1 to control the operation of described refrigeratory;

Described cooler package is divided into work cooler package, auxiliary cooler group and cooler package for subsequent use;

Described work cooler package comprises three groups of refrigeratorys;

Described auxiliary cooler group comprises one group of refrigeratory;

Described cooler package for subsequent use comprises one group of refrigeratory;

Each described refrigeratory is joined a described frequency converter.

10. described intelligent transformer frequency conversion air-cooled energy conserving system according to claim 9 is characterized in that:

Described power supply unit comprises two independences, primary power for subsequent use each other, and when a primary power broke down, another primary power came into operation, and sent alerting signal, simultaneously fault-signal was sent to control center by described remote control unit.

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