Power supply system utilizing waste heat of transformer in transformer substation

Abstract

The invention discloses a power supply system utilizing waste heat of a transformer in a transformer substation, which comprises a transformer shell, a semiconductor thermoelectric generator, a booster circuit and a transformer instrument, and is characterized in that one end of the semiconductor thermoelectric generator is in attached connection with the transformer shell through a heat conduction material; the other end of the semiconductor thermoelectric generator is connected with the input end of the booster circuit, and the output end of the booster circuit is connected with the transformer instrument; the semiconductor thermoelectric generator is configured to receive waste heat generated by the transformer shell and generate electromotive force through temperature difference, and the booster circuit is used for boosting voltage output by the semiconductor thermoelectric generator to constant target voltage needed by the transformer instrument, so that normal work of the transformer instrument is maintained. The power supply system is simple in structure, the waste heat of the transformer is used for supplying power to the transformer instrument, the waste heat is recycled and reasonably utilized, and the flexibility and reliability of the transformer instrument are improved.

Description

Technical Field

[0001] The present application relates to the technical field of equipment in a substation, and in particular to a power supply system utilizing waste heat of a transformer in a substation. Background Art

[0002] As a core device for power transmission widely used in power systems, transformers inevitably generate losses during the power conversion process, which are usually released into the atmosphere in the form of heat energy. The waste heat generated by the operation of transformers is currently mainly dissipated through cooling devices to ensure that the operating temperature of the transformer is maintained within a reasonable range, and the waste heat energy of the transformer itself is not effectively utilized. There is currently no plan for the reasonable and effective utilization of transformer waste heat.

[0003] At present, the power supply scheme for transformer instrument display equipment is as follows: a power supply box is set up near the transformer, two 380V power supplies are connected from the station power supply and after power switching, they are connected to the transformer body control cabinet and converted into the DC 24V power required by the transformer instrument through the switching power supply device.

[0004] The shortcomings of the current power supply scheme for transformer instrument display equipment are as follows: the power supply box of the substation mainly has 220V / 110V DC power supply and 380V AC power supply connected to the power supply system of the substation, and the transformer instrument adopts 24V DC power supply. The power supply box cannot directly power the instrument, but needs to be equipped with a power conversion device. The entire power supply circuit has undergone multi-stage conversion. In addition, if the dual power switching device in the power supply box fails, there is a risk of power failure of all instruments at the same time.

[0005] Therefore, there is an urgent need in this field to develop a power supply system that utilizes the waste heat of the transformer in the substation. The power supply system has a simple structure and utilizes the waste heat of the transformer to power the transformer instruments. It not only recovers the waste heat, but also reasonably utilizes the waste heat and improves the flexibility and reliability of the transformer instruments. Summary of the invention

[0006] The purpose of the present application is to provide a power supply system that utilizes the waste heat of the transformer in a substation. The power supply system has a simple structure and utilizes the waste heat of the transformer to power the transformer instruments. It not only recovers the waste heat, but also reasonably utilizes the waste heat and improves the flexibility and reliability of the transformer instruments.

[0007] The present application provides a power supply system utilizing transformer waste heat in a substation, comprising:

[0008] A transformer housing, a semiconductor temperature difference generator, a boost circuit and a transformer instrument, wherein one end of the semiconductor temperature difference generator is connected to the transformer housing by a heat conductive material, the other end of the semiconductor temperature difference generator is connected to the input end of the boost circuit, and the output end of the boost circuit is connected to the transformer instrument;

[0009] The semiconductor thermoelectric generator is configured to receive waste heat generated by the transformer housing and generate electromotive force using temperature difference. The boost circuit is used to boost the voltage output by the semiconductor thermoelectric generator to a constant target voltage required by the transformer instrument, thereby maintaining normal operation of the transformer instrument.

[0010] In another preferred example, the thermally conductive material includes thermally conductive silicone grease.

[0011] In another preferred example, the semiconductor thermoelectric generator includes a plurality of N-type semiconductors and P-type semiconductors connected in series.

[0012] In another preferred example, the semiconductor temperature difference generator further includes a conductive copper bus and the thermal conductive silicone grease.

[0013] In another preferred example, the thermal conductive silicone grease is located between the transformer housing and the N-type semiconductor and the P-type semiconductor.

[0014] In another preferred example, the input end of the boost circuit includes a positive terminal of the boost circuit and a negative terminal of the boost circuit, the positive terminal of the boost circuit is connected to the P-type semiconductor, and the negative terminal of the boost circuit is connected to the N-type semiconductor.

[0015] In another preferred example, the boost circuit includes an energy storage inductor, a switch tube, a diode and a filter capacitor.

[0016] In another preferred example, the voltage boost circuit is a Boost converter, and the Boost converter includes an energy storage inductor, a switch tube, a diode and a filter capacitor.

[0017] In another preferred example, the system also includes a voltage feedback control loop, which is configured to enable the semiconductor temperature difference generator to provide the required constant target voltage for the transformer instrument, and the voltage feedback control loop includes an input current detection unit, a microprocessor control circuit and an output voltage detection unit.

[0018] In another preferred example, the input current detection unit is used to detect the current value output by the semiconductor thermoelectric generator, and the output voltage detection unit is used to detect the output voltage of the output end of the boost circuit.

[0019] In another preferred example, the microprocessor control circuit includes a PID controller, and the PID controller is configured to adjust the on and off time of the switch tube according to a set voltage value.

[0020] In another preferred embodiment, when the switch tube is turned on, the semiconductor temperature difference generator charges the energy storage inductor, and the diode is in a closed state at this time to prevent the filter capacitor from discharging; when the switch tube is turned off, the energy storage inductor discharges the filter capacitor and the transformer instrument, the inductor current begins to decrease slowly, and the output voltage U o =U i +U L , where U L is the voltage of the energy storage inductor.

[0021] For the inductor, when the switch is turned on, U on =U i , when the switch is turned off, U off =U o -U i , according to the volt-second balance principle, we can get U i *T D =(U o -U i )*(T S -T D ), (Ts refers to the total time of the switch 32 being turned on and off, T D Refers to the time when the 32 tube is turned on), D = T D / T S . Simplified to Uo=U i / (1-D), semiconductor thermoelectric generator output voltage Ui=∑α ab *(T1-T2).

[0022] In another preferred embodiment, the output voltage at the output end of the boost circuit is U o =∑α ab *(T1-T2) / (1-D), where α ab is the phase Seeback coefficient of N-type semiconductor and P-type semiconductor, the unit is V / K;

[0023] T1 is the temperature of the transformer housing, T2 is the ambient temperature, the unit is K;

[0024] D is the modulation duty cycle output by the microprocessor control circuit, and its range is 0 to 1.

[0025] In another preferred embodiment, the power generated by the semiconductor thermoelectric generator matches the power required by the transformer meter. The power generated by the semiconductor thermoelectric generator is about 20W, and the power required by the transformer meter is in the range of several watts to more than ten watts.

[0026] It should be understood that within the scope of the present invention, the above-mentioned technical features of the present invention and the technical features specifically described below (such as embodiments) can be combined with each other to form a new or preferred technical solution. Due to space limitations, they will not be described one by one here. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the prior art descriptions are briefly introduced below. It should be understood that the drawings described below are only some implementation examples of the present invention, and ordinary technicians in this field can also obtain other implementation examples based on these drawings without paying creative work.

[0028] Figure 1 is a schematic diagram of a power supply system utilizing waste heat of transformers in a substation according to the present application;

[0029] Figure 2 is a schematic structural diagram of a boost circuit according to an embodiment of the present application;

[0030] Figure 3 It is a structural schematic diagram of a semiconductor thermoelectric generator according to the present application.

[0031] In the accompanying drawings, the following are marked:

[0032] 1- Transformer housing

[0033] 2-Semiconductor thermoelectric generator

[0034] 21-N-type semiconductor

[0035] 22-P type semiconductor

[0036] 23-Conductor copper bar

[0037] 24- Thermal grease

[0038] 3-Boost circuit

[0039] 31-Energy storage inductor

[0040] 32-Switch tube

[0041] 33-Diode

[0042] 34-Filter capacitor

[0043] 4- Transformer Instrument

[0044] 5- Input current detection unit

[0045] 6-Microprocessor control circuit

[0046] 7-Output voltage detection unit DETAILED DESCRIPTION

[0047] Through extensive and in-depth research, the inventors have developed for the first time a power supply system that utilizes transformer waste heat in a substation. The system effectively recovers the transformer waste heat based on the Seebeck effect of semiconductor materials, uses the transformer waste heat for temperature difference power generation, and converts the fluctuating voltage output by the temperature difference generator into the steady-state voltage required by the instrument through a BOOST converter, thereby constructing a reliable distributed power supply form. In addition, by matching the energy demand and energy consumption characteristics of the transformer distributed instrument (load), a new transformer instrument power supply method is proposed, which not only refines the use of energy, but also improves the reliability of instrument power supply, is beneficial to the needs of equipment safety, stability, and reliability, and also promotes the green and energy-saving development of the industry.

[0048] In the following description, many technical details are provided to help readers better understand the present application. However, those skilled in the art can understand that the technical solution claimed in the present application can be implemented even without these technical details and various changes and modifications based on the following embodiments.

[0049] the term

[0050] As used herein, transformer instrumentation refers to "transformer oil level gauge, transformer oil level thermometer, transformer winding thermometer, etc."

[0051] Thermoelectric power generation: using the temperature difference between high and low temperature heat sources to convert thermal energy into electrical energy;

[0052] Low-grade waste heat: waste heat with low concentration and low energy generated by heat sources such as sensible heat materials with a temperature below 800°C in industrial production and other activities;

[0053] It should be noted that in the application documents of this patent, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that the process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "including one" do not exclude the existence of other identical elements in the process, method, article or device including the elements. In the application documents of this patent, if it is mentioned that an action is performed according to an element, it means that the action is performed at least according to the element, which includes two situations: performing the action only according to the element, and performing the action according to the element and other elements. Expressions such as multiple, multiple, and multiple include 2, 2 times, 2 kinds, and more than 2, more than 2 times, and more than 2 kinds.

[0054] In the present invention, all directional indications (such as up, down, left, right, front, back, etc.) are only used to explain the relative position relationship, movement status, etc. between the components in a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0055] This application has at least one of the following advantages

[0056] (a) The power supply system of the present application that utilizes the waste heat of the transformer in the substation effectively recovers the low-grade heat source of the transformer. The conversion and utilization method is simple and efficient. Considering the huge total number of transformers in the power grid system, the energy saving and carbon reduction benefits brought by the present application for energy utilization are very considerable;

[0057] (b) Compared with the traditional power supply method, the power supply system using the waste heat of the transformer in the substation of the present application is more compact and sophisticated, and there is no multi-stage power conversion unit. It can reduce the risk of a single device failure affecting the operation of instrument equipment on a large scale, improve the energy utilization rate of the substation, and improve the reliability of instrument power supply while refining the use of energy, which is conducive to the safety, stability and reliability of equipment and promotes the green energy-saving development of the industry;

[0058] (c) The power supply system using transformer waste heat in the substation of the present application solves the two technical problems that the low-grade waste heat generated by the transformer operation is difficult to effectively utilize and the power supply scheme of the transformer detection instrument is complicated. Based on the principle of semiconductor temperature difference power generation, the low-grade waste heat generated by the transformer operation is converted into electrical energy, the transformer body is used as the energy source, and the output voltage is adjusted in real time according to the transformer operating conditions and ambient temperature changes, and a simple circuit is used to directly provide stable and reliable power supply to various low-power instruments of the transformer;

[0059] (d) The power supply system using transformer waste heat in the substation of the present application effectively utilizes the low-grade waste heat generated by the operation of the transformer, opens up a path for waste heat utilization of heat-generating electrical equipment such as transformers from the underlying principle, refines energy utilization, improves energy utilization rate, and has considerable energy-saving and carbon-reduction benefits from the perspective of the total amount of equipment. At the same time, it also provides a convenient solution for the power supply of various distributed instruments;

[0060] (e) The power supply system using transformer waste heat in the substation of the present application uses the main equipment body (transformer) to power the instrument, and measures to improve the flexibility and reliability of the transformer oil level gauge, transformer oil level thermometer, and transformer winding thermometer;

[0061] (f) The power supply system utilizing the waste heat of the transformer in the substation of the present application adjusts the power supply system status in real time according to the set voltage value to meet the power supply demand of the instrument.

[0062] A power supply system utilizing transformer waste heat in a substation

[0063] The present application provides a power supply system utilizing waste heat of a transformer in a substation, the system comprising a transformer housing 1, a semiconductor temperature difference generator 2, a boost circuit 3 and a transformer meter 4, one end of the semiconductor temperature difference generator 2 being bonded and connected to the transformer housing 1 via a heat-conducting material, the other end of the semiconductor temperature difference generator 2 being connected to an input end of the boost circuit 3, and an output end of the boost circuit 3 being connected to the transformer meter 4; preferably, the heat-conducting material comprises a thermally conductive silicone grease 24.

[0064] The semiconductor temperature difference generator 2 is configured to receive the waste heat generated by the transformer housing 1 and generate electromotive force using the temperature difference. The boost circuit 3 is used to boost the voltage output by the semiconductor temperature difference generator 2 to the constant target voltage required by the transformer meter 4, thereby maintaining the normal operation of the transformer meter 4.

[0065] Preferably, the semiconductor thermoelectric generator 2 comprises a plurality of N-type semiconductors 21 and P-type semiconductors 22 connected in series. The thermal conductive silicone grease 24 is located between the transformer housing 1 and the N-type semiconductors 21 and P-type semiconductors 22 .

[0066] Preferably, the semiconductor temperature difference generator 2 further includes a conductive copper bus 23 and the thermal conductive silicone grease 24 .

[0067] Preferably, the input end of the boost circuit 3 includes a positive terminal of the boost circuit and a negative terminal of the boost circuit, the positive terminal of the boost circuit is connected to the P-type semiconductor 22 , and the negative terminal of the boost circuit is connected to the N-type semiconductor 21 .

[0068] Preferably, the boost circuit 3 is a Boost converter, and the boost circuit includes an energy storage inductor 31 , a switch tube 32 , a diode 33 and a filter capacitor 34 .

[0069] Preferably, the system further comprises a feedback control loop, the feedback control loop being configured to enable the semiconductor thermoelectric generator 2 to provide the required constant target voltage for the transformer meter 4, the feedback control loop comprising an input current detection unit 5, a microprocessor control circuit 6 and an output voltage detection unit 7. Preferably, the input current detection unit 5 is used to detect the current value of the energy storage inductor 31 of the input boost circuit, and the output voltage detection unit 7 is used to detect the output voltage at the output end of the boost circuit 3.

[0070] Preferably, the microprocessor control circuit 6 includes a PID controller, and the PID controller is configured to adjust the on and off time of the switch tube 32 according to a set voltage value.

[0071] When the switch tube 32 is turned on, the semiconductor thermoelectric generator 2 charges the energy storage inductor 31, and the diode 33 is in a closed state at this time to prevent the filter capacitor 34 from discharging; when the switch tube 32 is turned off, the energy storage inductor 31 discharges the filter capacitor and the transformer instrument, and the inductor current begins to decrease slowly, and the output voltage U o =U i +U L , where U L is the voltage of the energy storage inductor, U o is the output voltage of the boost circuit, U i is the input voltage of the boost circuit.

[0072] To make the purpose, technical solution and advantages of the present invention clearer, the embodiments of the present invention will be further described in detail below in conjunction with the accompanying drawings. It should be understood that these are only some examples that the present invention may take for the reader, but are not intended to limit the scope of the present invention.

[0073] Example 1

[0074] like Figure 1As shown, the present application provides a power supply system utilizing the waste heat of transformers in a substation. The system is a transformer instrument power supply system based on the principle of semiconductor temperature difference power generation, which includes: a semiconductor temperature difference generator 2, a boost circuit 3, an input current detection unit 5, an output voltage detection unit 7, a microprocessor control circuit 6 (in this embodiment, the microprocessor control circuit 6 is a PID controller), a transformer housing 1, and a transformer instrument 4. Among them, the transformer housing 1 provides an energy source for the power supply system, and the transformer instrument 4 is a load for the power supply system. All of the above devices are arranged around the transformer. Figure 2 As shown, the boost circuit 3 is a Boost converter, which includes an energy storage inductor 31 , a switch tube 32 , a diode 33 and a filter capacitor 34 .

[0075] One end of the semiconductor thermoelectric generator 2 is attached to the transformer housing 1, and the other end is connected to the boost circuit 3. Due to the fixed temperature difference between the two ends of the semiconductor, an electromotive force is generated. Considering that there are many factors affecting the change of ambient temperature and the temperature of the transformer housing 1 (shell), and the transformer instrument 4 requires a power supply with a relatively stable voltage, the boost circuit 3 is responsible for stabilizing the output voltage.

[0076] In this embodiment, the input current detection unit 5 is used to detect the current value of the energy storage inductor 31 of the input boost circuit 3, and the output voltage detection unit 7 is used to detect the output voltage of the output end of the boost circuit 3. The output voltage value of the output end of the boost circuit 3 detected by the output voltage detection unit 7 and a set fixed reference voltage value constitute the voltage outer loop negative feedback regulation, and the input current detection unit 5 is used to detect the current value of the energy storage inductor 31 of the input boost circuit 3 and the voltage outer loop regulation output value (i.e., the target current value) to constitute the current inner loop negative feedback regulation, and the voltage and current negative feedback regulation control is realized by the microprocessor control circuit 6 (built with operational amplifiers, resistors, and capacitors), and the appropriate PID (proportional integral differential) parameters are set according to the system characteristics, so as to continuously provide a stable voltage source for the transformer instrument 4, and achieve the purpose of recycling the waste heat of the transformer.

[0077] According to the set voltage value, the PID controller adjusts the on and off time of the switch tube 32. When the switch tube 32 is turned on, the semiconductor thermoelectric generator 2 charges the energy storage inductor 31, and the diode 33 is in a closed state at this time to prevent the filter capacitor 34 from discharging; when the switch tube 32 is turned off, the energy storage inductor 31 discharges the filter capacitor 34 and the transformer instrument 4, and the inductor current begins to decrease slowly, and the output voltage U o =U i +U L .

[0078] For the inductor, when the switch tube 32 is turned on, U on =U i , when the switch tube 32 is turned off, Uoff =U o -U i , according to the volt-second balance principle, U i *T D =(U o -U i )*(T S -T D ). Wherein, Ts refers to the total time of switching on and off of the switch tube 32, T D Refers to the time when the 32 tube is turned on, D = T D / T S , U o is the output voltage of the boost circuit, U i is the input voltage of the boost circuit.

[0079] Therefore, U o Simplified to U o =U i / (1-D), semiconductor thermoelectric generator output voltage U i =∑α ab *(T1-T2), as described in detail below.

[0080] The structure of the semiconductor thermoelectric generator 2 of the present application is as follows Figure 3 As shown, it includes an N-type semiconductor 21, a P-type semiconductor 22, a current-conducting copper bus 23, and a thermally conductive silicone grease 24. The figure also shows the transformer housing 1. When the semiconductor thermoelectric generator 2 is attached to the transformer body (i.e., the transformer housing 1), the thermally conductive silicone grease 24 can not only effectively conduct the residual heat of the transformer, but also insulate the closed current loop of the thermoelectric generator from the transformer housing to reduce the impact on the main equipment. The N-type semiconductor 21 and the P-type semiconductor 22 form a pair of thermocouples. According to the principle of thermoelectric power generation, the thermoelectric electromotive force △U=α ab *(T1-T2),

[0081] α ab is the phase Seeback coefficient of the N-type semiconductor 21 and the P-type semiconductor 22, unit: V / K;

[0082] T1 and T2 are the temperatures at the heat source (transformer housing) and the cold source (environment), unit: K.

[0083] The voltage and current generated by a single thermocouple are relatively small. The system of the present application increases the output voltage and current of the semiconductor thermoelectric generator 2 by connecting multiple thermocouple units in series and parallel. According to the volt-second balance principle, the voltage value U output by the BOOST boost circuit is o =U i / (1-D), as described above.

[0084] U iBOOST input voltage, unit: V / K;

[0085] D is the modulation duty cycle output by the microprocessor control circuit 6, and its range is 0 to 1.

[0086] The output voltage U of the power supply system of this application o =∑α ab *(T1-T2) / (1-D), the corresponding parameters can be adjusted according to the parameter requirements of the transformer instrument 4 to meet its 24V power supply demand.

[0087] A large number of technical features are recorded in the specification of this application, which are distributed in various technical solutions. If all possible combinations of technical features of this application (i.e., technical solutions) are to be listed, the specification will be too long. In order to avoid this problem, the various technical features disclosed in the above-mentioned invention content of this application, the various technical features disclosed in the various embodiments and examples below, and the various technical features disclosed in the accompanying drawings can be freely combined with each other to form various new technical solutions (these technical solutions are all deemed to have been recorded in this specification), unless the combination of such technical features is technically infeasible. For example, in one example, feature A+B+C is disclosed, and in another example, feature A+B+D+E is disclosed, and features C and D are equivalent technical means that play the same role. Technically, only one can be used, and it is impossible to use them at the same time. Feature E can be combined with feature C technically. Then, the solution of A+B+C+D should not be deemed to have been recorded because it is technically infeasible, and the solution of A+B+C+E should be deemed to have been recorded.

[0088] All documents mentioned in this application are considered to be included in the disclosure of this application as a whole, so that they can be used as the basis for modification when necessary. In addition, it should be understood that after reading the above disclosure of this application, those skilled in the art can make various changes or modifications to this application, and these equivalent forms also fall within the scope of protection claimed in this application.

Claims

1. A power supply system utilizing transformer waste heat in a substation, characterized in that: include: A transformer housing (1), a semiconductor temperature difference generator (2), a boost circuit (3) and a transformer instrument (4), wherein one end of the semiconductor temperature difference generator (2) is connected to the transformer housing (1) by means of a heat conductive material, the other end of the semiconductor temperature difference generator (2) is connected to the input end of the boost circuit (3), and the output end of the boost circuit (3) is connected to the transformer instrument (4); The semiconductor temperature difference generator (2) is configured to receive waste heat generated by the transformer housing (1) and generate electromotive force using temperature difference, and the boost circuit (3) is used to boost the voltage output by the semiconductor temperature difference generator (2) to a constant target voltage required by the transformer meter (4), thereby maintaining the normal operation of the transformer meter (4).

2. The system according to claim 1, characterized in that The heat-conducting material includes heat-conducting silicone grease (24).

3. The system according to claim 2, characterized in that The semiconductor temperature difference generator (2) comprises a plurality of N-type semiconductors (21) and P-type semiconductors (22) connected in series.

4. The system according to claim 3, characterized in that The input end of the boost circuit (3) comprises a positive terminal of the boost circuit and a negative terminal of the boost circuit, the positive terminal of the boost circuit is connected to the P-type semiconductor (22), and the negative terminal of the boost circuit is connected to the N-type semiconductor (21).

5. The system according to claim 1, wherein: The boost circuit comprises an energy storage inductor (31), a switch tube (32), a diode (33) and a filter capacitor (34).

6. The system according to claim 5, characterized in that The system further comprises a feedback control loop, which is configured to enable the semiconductor temperature difference generator (2) to provide a required constant target voltage for the transformer instrument (4), and the feedback control loop comprises an input current detection unit (5), a microprocessor control circuit (6) and an output voltage detection unit (7).

7. The system according to claim 6, characterized in that The input current detection unit (5) is used to detect the current value of the energy storage inductor (31) input into the boost circuit, and the output voltage detection unit (7) is used to detect the output voltage at the output end of the boost circuit (3).

8. The system according to claim 7, characterized in that The microprocessor control circuit (6) comprises a PID controller, and the PID controller is configured to adjust the on and off time of the switch tube (32) according to a set voltage value.

9. The system according to claim 8, characterized in that The output voltage at the output end of the boost circuit (3) is U o =∑α ab *(T1-T2) / (1-D), Among them, α ab is the phase Seeback coefficient of N-type semiconductor and P-type semiconductor, the unit is V / K; T1 is the temperature of the transformer housing, T2 is the ambient temperature, the unit is K; D is the modulation duty cycle output by the microprocessor control circuit, and its range is 0 to 1.

10. The system according to claim 1, wherein: The power generated by the semiconductor temperature difference generator (2) matches the power required by the transformer meter. The power generated by the semiconductor temperature difference generator (2) is about 20W, and the power required by the transformer meter is in the range of several watts to more than ten watts.

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