WO2009000159A1

WO2009000159A1 - Low energy-consuming series current transformer for 1-1000 kv transformer detect

Info

Publication number: WO2009000159A1
Application number: PCT/CN2008/001220
Authority: WO
Inventors: Cuipei Hu; Yan Liang
Original assignee: Cuipei Hu; Yan Liang
Priority date: 2007-06-25
Filing date: 2008-06-24
Publication date: 2008-12-31

Abstract

A low energy-consuming series current transformer for 1-1000 KV transformer detect, which is a core through typed current transformer, includes an iron core (1), a primary coil (2), a secondary coil (3). It uses the high pressure of 10-1000 KV series insulating cable as primary bus bar. The secondary coil (3) connects to the current coil of an electric meter. The secondary coil (3) connects in series to an ammeter (5) and a voltmeter (4) that in parallel connection. One end of the ammeter (5) and the voltmeter (4) is connected with an end of the secondary coil (3) through an on-off switch (7). Another end of the ammeter (5) and the voltmeter (4) is connected with another end of the secondary coil (3) through a lead. The transformer is simple in structure, consumes low energy, is safe and reliable, and convenient to use.

Description

Low-energy series current transformer for detecting 1-1000KV transformer

The invention relates to a current transformer for high-voltage current monitoring and electric energy metering, in particular to a low-energy series current transformer for detecting 1-1000KV transformer. Background technique

The current current transformers can be divided into dry type, solid type, oil immersed type and gas type according to the insulation method. The commonly used insulating mediums are epoxy resin, insulating oil and sulfur hexafluoride gas. Dry and solid current transformers are generally suitable for voltages below 35kV. Current transformers with higher voltage levels, such as 110~500kV or even 750kV, 1000kV, can only be insulated with oil insulation and sulfur hexafluoride gas. Since oil insulation and sulfur hexafluoride gas insulation have the disadvantage of being easily leaked, and oil insulation leaks, there is a danger of explosion. Therefore, the existing high-voltage current transformers are provided with a fuel tank or a gas tank, a metal expansion valve and a sealing device, so that the structure of the current transformer is complicated, expensive, and it is difficult to ensure safety and reliability.

"Electrician Handbook" edited by nine famous cities such as Shanghai, Beijing, Tianjin, "Electrical Engineering Handbook", "University Physics", "Electrical Science", "Electromagnetics" edited by 500 research institutes, universities and colleges "The circuit and magnetic circuit", "electromagnetic field", "electrodynamics", "quantum electrodynamics" and "transformer design" and other works in the second open circuit of the current transformer due to the traditional conclusion of the lineage: "Second Open circuit operation will produce hundreds of volts, thousands of volts, or even tens of thousands of volts that endanger the safety of people and equipment: the core is severely hot and burnt." Therefore, "absolutely do not allow the current transformer to open twice!". The world literature shows that: The current transformers for detecting high-voltage three-phase currents are connected to the live line of the three-phase power transformer, and the linear theory of the mid-18th century is used to agree that the current transformer (hereinafter referred to as TA) and the secondary open circuit are generated. High pressure burned out.

However, the inventors Hu Cuipei and Liang Yan Research Group (Current Transformer Nonlinear Test and Research Center) have verified the above conclusions by 567,000 secondary open circuit voltage tests. The test results are as follows:

1. LQG series that have been eliminated 30 / 5, 50 / 5, 80 / 5, 100 / 5, 150 / 5, 200 / 5, 300 / 5, 400 / 5, 500 / 5, 600 / 5, 800 / 5, 1000 / 5, 1500 / 5, 2000 / 5 15 current transformers, the secondary open circuit voltage running at rated current is: 12. 8 volts to 85. 5 volts; its corresponding primary pressure drop is 2. 13 volts to 0. 21 volts.

2. LMK, LMK, LMZ, LMZ^ LMZJ, LMZJ, six new types of transformers, with ratios of 150 / 5, 200 / 5, 300 / 5, 400 / 5, 500 / 5, 600 / 5, 800 / 5, 1000 / 5, 1500 /5, 2000/ 5, ten kinds of current transformers with different ratios, the primary circuit is single-turn bus-through type, running at rated primary current, and the secondary winding voltage of LMZ^ series is between 2.8 volts and 36 volts. The corresponding pressure drop is between 0.093 volts and 0.09 volts, and the pressure drop of the individual county products is 0.12.

3. Four series of LY, LQJ, LFC and LFCD with working voltage of 10 kV 30 / 5, 40 / 5, 50/5, 60/5, 80/5, 100/5, 150/5, 200/ 5, 300 / 5, 400/5, 500 / 5, 600 / 5, 800 / 5, 1000 / 5, 1500 / 5, 2000 / 5 16 kinds of current transformers running at rated primary current, measuring 0.5 current The secondary open circuit voltage of the coil is between 12.7 volts and 83.6 volts; the secondary open circuit voltage of the 3-level voltage coil is between 24.8 volts and 345 volts. Its voltage drop is 2.12 volts to 0.21 volts! The test values of all technical parameters prove that the secondary open circuit voltage of the current transformer is the application parameter that is continuously reduced along with the development of science and technology, social progress, material renewal, structural optimization and process change. All the original products have been operated for the 14th anniversary. No case of burnout was found.

The measured results show that: TA secondary open circuit voltage is low, dynamic internal resistance is small, and over current does not generate heat.

With the advancement of human non-linear theory of human fringe science in the 1930s, we realized that the trend of magnetic permeability of human soft magnetic materials is that the maximum value of magnetic permeability is u max: 2500000 Gs / Oe ( American quantum electrodynamics cited), 1500000Gs / Oe, 300000Gs / Oe, 200000Gs / Oe, lOOOOOOS / Oe, 12000Gs / Oe, 8000Gs / Oe with the increase of magnetic field, will inevitably fall to vacuum permeability, u0 = lGs / Os .

In response to the above changes, the research team believes that the above physical quantities must not be treated as constants. For this research group, the magnetization curve of common materials was also studied to test the effective value of the current transformer, so that the effective value and the test value have a one-to-one correspondence. The research team used binary differential equations to write a new mathematical model of 127 university formulas. The model is characterized by a wide open magnetic saturation condition under the secondary open circuit condition of the current transformer. The secondary open circuit voltage is a straight line in a wide magnetic saturation state and parallel to the X axis in a wide magnetic saturation region.

In response to the above parameters and new findings, the research group and Tsinghua University, Peking University, China Ministry of Power Industry Science and Technology Department, China Thermoelectric Engineering Society, National Natural Science Foundation Committee Secretary Yuan Haibo, Institute of Electrical Engineering, Chinese Academy of Sciences Liu Tingwen, Peking University Physics The dean of the department and the famous physicist of Tang University, Tang Zhensong, have made academic exchanges and defenses for the academic group. The test results and conclusions have also been authenticated and forwarded by the Ministry of Education, the Ministry of Science and Technology, and the Shandong Bureau of the Chinese Academy of Sciences. The Department of Science and Technology of the Ministry of Power Industry and the China Society of Thermoelectric Engineering have conducted special research and confirmation. Summary of the invention

The object of the present invention is to provide a low-energy series current transformer for detecting 1-1000KV transformers which is simple in structure, low in energy consumption, safe and reliable, and convenient to use, which is developed by using the above-mentioned scientific new findings.

In order to achieve the above object, the present invention detects a low-energy series current transformer of a 1-1000 KV transformer, and is a bus-through core current transformer, which comprises a core, a primary coil, and a secondary coil, and is particularly useful in the use of 10- The 1000kV series high-voltage insulated cable is used as a through-core bus. It is based on the existing shortcomings of dry, solid, oil-immersed and sulphur hexafluoride gas-type insulated current transformers, using the currently developed 10_500kV or 500-1000kV high-voltage insulated cable as a through-core bus. The secondary winding is modified according to the current method to be wound on the iron core and cast epoxy resin for composite insulation, and then the primary through-core busbar, the secondary winding and the iron core are integrated into a low-energy environment-friendly current transformer. . The utility model is characterized in that the primary through-core busbar is directly wound by a high-voltage cable, and the insulating layer of the high-voltage cable is an insulating layer between the primary busbar and the secondary winding and the iron core, because the high-voltage cable insulation layer is made of ultra-high voltage composite insulation, according to Different voltage withstand voltage, cable withstand voltage up to 10~500kV, higher-grade high-voltage cable, withstand voltage even up to 500~1000kV without breakdown, no need to carry on between busbar cable and secondary winding and iron core Complex oil immersion and sulfur hexafluoride gas insulation. Due to the use of composite insulated high voltage cable, the insulation cable can withstand voltages up to

10~1000kV without breakdown. Therefore, the secondary winding and the iron core are cast and insulated with epoxy resin composite material, and special shielding and other devices are added to meet the requirements. The fabricated current transformer can be connected to the high voltage line. Current monitoring and energy metering. The 10-1000kV series low-energy environment-friendly current transformer of the invention has the advantages of compact structure, low cost and convenient use compared with the conventional products due to the reduction of the fuel tank (cabinet), the gas box, the metal expansion and the sealing device. The operation has low energy consumption, high safety and reliability, and no pollution of insulating oil and sulfur hexafluoride gas. It is safe and environmentally friendly and has great promotion value.

As an optimization, the secondary coil is connected to the current coil of the meter. So designed, it has the advantages of simple structure, low energy consumption, energy saving, safety and reliability, and convenient use.

As an optimization, the voltage coil of the meter is connected to a 220V or 380V line. The product thus designed has the advantages of simple structure, energy saving, safety and reliability, and convenient use.

As an optimization, the secondary coil is connected in series with the ammeter and the voltmeter in parallel, one end of the ammeter and the voltmeter is connected to one end of the secondary coil through a two-position switch, and the other end of the ammeter and the voltmeter is connected to the other end of the secondary coil through a wire. So designed, when the voltage needs to be measured, the two-position switch is operated to make the voltmeter and the second The coils are connected in series to disconnect the current meter from the secondary coil; when current measurement is required, the two-position switch is operated to make the ammeter and the secondary coil are connected in series, and the connection between the voltmeter and the secondary coil is disconnected; , low energy consumption, safe and reliable, easy to use.

As an optimization, one end of the two-position switch connects one end of the ammeter to one end of the secondary coil, and the other end of the two-position switch connects one end of the voltmeter to one end of the secondary coil. The product thus designed has the advantages of simple structure, low energy consumption, safety and reliability, and convenient use.

As an optimization, high-voltage insulated cables are made of single-core or triple-core or multi-core cables, and cable insulation is made of polyethylene cross-linked insulation or self-contained oil-filled paper.

As an optimization, the current transformer is a single-turn busbar core type, LMK, LMK^ LMZ, LMZ, LMZJ, LMZJ, six series of new current transformers; primary coil series three-phase power transformer fire line or primary coil series three The neutral line of the phase power transformer. So designed, the primary coil series three-phase power transformer zero line has broken through the existing design schemes of all human beings, and there is no danger of high voltage and personal safety; it has the advantages of simple structure, low energy consumption, safety and reliability, and convenient use. But the fire line helps prevent electricity theft.

As an optimization, the current transformer is a single-turn busbar core type, LMK LMK^ LMZ, LMZ, LMZJ, LMZJt six series of new current transformers; the live and neutral wires of the power transformer are respectively connected to the current sensor, high voltage insulation The cable acts as the live wire of the primary coil in series with the live wire of the three-phase power transformer, and the copper wire acts as the zero wire of the three-phase power transformer of the primary bus of the primary coil. This design, first of all, can save the cost of threading the wire, and, in addition, can be used to check for electricity; because, stealing electricity is usually connected to the appliance and then no longer connected to the zero line, but directly grounded, so the current reading of the live and neutral lines A difference will appear, that is, the fire line reading must be greater than the zero line reading.

In order to better understand the significance of the technical solution of the present invention, the nonlinear theoretical research results of the volt-ampere characteristics of the current transformer conducted by the inventors are as follows - I. Test purpose: According to the conventional theory, the current transformer is in operation, the secondary circuit The open circuit will generate high voltages of several hundred volts to several thousand volts or even tens of thousands of volts, and that the open circuit voltage of the secondary circuit increases with the increase of the primary current, and there is a linear relationship between the open circuit voltage and the primary current. As the current transformer generates high voltage and severe heat, the current transformer burns out. Based on this traditional theory, the high-voltage current transformers currently used in order to prevent high-voltage breakdown and heat-burning, to prevent the structure from being layered, resulting in a large volume and high price, thereby increasing the burden on the power sector. This test is to test and study the operating characteristics of the primary and secondary circuits of various series of current transformers with different specifications to establish nonlinearity. On this basis, the structure and connection method of the current transformer are improved, and the new production of current transformer is researched and developed. 2. Test materials: i. Test sample: Liuzhou Transformer Factory, Shanghai Transformer Factory

LMZJ1-0.5KV series, current transformer with 0.5 accuracy and BH0.66KV series produced by Suzhou Sanyou Transformer Factory, current transformer with 0.2 accuracy. 2. Test instruments: Power supply voltage regulators, power supply voltage regulators, high current transformers, digital clamp ammeters, digital multimeters, electric meters and other sophisticated test instruments.

Third, the test method: 1, in one load circuit operation, adjust the input current of the primary circuit is 1 times, 2 times up to several times or even tens of times the rated current, measure the open circuit voltage of the current transformer, to determine once Loop operation volt-ampere characteristics. 2. When 0.2-5.0A current is injected into the secondary circuit, the voltage drop across the secondary path of various current transformers is tested to determine the secondary volt-ampere characteristics of the current transformer.

IV. Test results: 1. The volt-ampere characteristic test results of the current transformer at one rated circuit and rated current and several times to several tens of times the rated current (ie, overcurrent) are shown in Table 1, and according to Table 2 The relationship between the secondary circuit open circuit voltage U ₂ and the primary circuit injection current is shown in Figure 1. 2. The test results of the secondary volt-ampere characteristics of the current transformer are shown in Table 2, and the relationship between the secondary circuit voltage U ₂ and the injection current 1 ₂ plotted according to Table ₂ is shown in Figure 2.

V. Analysis of test results:

1. From the test results of the primary volt-ampere characteristic of the current transformer, it can be found that the secondary open circuit voltage of the current transformer increases with the increase of the ratio, but no high voltage is generated, even the maximum ratio of 3000/5 current. For transformers, the open circuit voltage of the primary circuit at rated current is only 34.9 volts to 38.2 volts.

2. The secondary open circuit voltage of the current transformer will increase at the initial stage with the increase of the input current of the primary circuit, but the increase is not large. For example, the maximum increase is 3000/5 transformer, when the rated current is doubled. When it is increased to 2.5 times, the secondary open circuit voltage is only increased by 0.8 to 2.3 volts, and the increase is only 2.2% to 5.0% instead of 150%, and as the current increases, the open circuit voltage gradually becomes stable and decreases. Therefore, the ratio of voltage to current is not a constant at all, and there is no linear relationship.

3. When the multiple of the primary operating current is increased to a certain extent, the open circuit voltage of some current transformers will gradually decrease. For example, 800/5 to 1000/5 transformers are rated at 4 to 6 times, 400/5 to 600. The current transformer of /5 is rated at 7 to 9 times, and the current transformer of 100/5 to 300/5 is at 7 to 15 times rated current, and the open circuit voltage of the secondary circuit is degraded. 4. Injecting 0.2-5.0A current into the secondary path, the voltage drop of the secondary circuit increases with the increase of current and ratio, but the pressure drop is still not high, even if the maximum ratio is 3000/5. The voltage drop of the electric current transformer at rated current of 5.0A is also only 38.9-51.1 volts. Moreover, when the large transformer is at 0.2A, the secondary circuit voltage drop has reached 77%-84% of the voltage drop at the rated current (5A). When the current is increased by 2400%, the current is only increased by 16%-23%. The ratio of voltage to current is reduced from 150.3-221 at 0.2 A to 7.7-10.2 at 5A. Therefore, the ratio of voltage to current is not a constant at all. . If the permeability is regarded as a constant according to the traditional linear theory, the ratio of the open circuit voltage to the input current is assumed as a constant. Taking the 1#3000/5 current transformer as an example, the voltage drop at 0.2A is 30.1 volts, 5A. The pressure drop at the time should be estimated to be 762.5 volts. However, the actual pressure drop at 5A is only 38.9 volts, which is only one-ninth of the linear theoretical estimate.

It is based on the misunderstanding of the traditional linear theory that the current transformer is open twice and the impedance is infinite. Therefore, a large voltage drop is generated at one time, and the calculation is substituted into the formula Q=0.24IUt. It is considered that the transformer will generate a large amount of heat and cause mutual inductance. The device is hot and burnt. At the same time, it is speculated that the secondary open circuit will generate a high open circuit voltage, and the open circuit voltage is as high as several hundred, several thousand, or even tens of thousands of volts. Therefore, the layer is fortified during the design and use of the current transformer, which makes the product structure complicated and expensive. The nonlinear theory established in the research of this test, the structural optimization of current transformer products, and the improvement of the connection method, have important guiding significance for the development of safe, low-cost, cost-effective products.

At present, 2000/5 current transformer 54KV price 50 yuan, 110KV current transformer price 40,000 yuan, 220KV current transformer price 80,000 yuan, 500KV current transformer price 280,000 yuan, 750-100KV current mutual inductance The device has not yet been used; after using the technical solution of the invention, the cost can be greatly reduced and social resources can be saved.

Therefore, after adopting the above innovative technical solution, the low-energy series current transformer of the invention for detecting 1-1000KV transformer has the advantages of simple structure, low energy consumption, safety, reliability and convenient use. DRAWINGS

1 is a circuit schematic diagram of a first embodiment of a low energy series current transformer for detecting a 1-1000 KV transformer according to the present invention;

2 is a schematic structural view of a first embodiment of a low-energy series current transformer for detecting a 1-1000 KV transformer according to the present invention;

3 is a circuit schematic diagram of a second embodiment of a low-energy series current transformer for detecting a 1-1000 KV transformer according to the present invention; 4 is a schematic circuit diagram of a three-phase current detection of a primary side of a 1-1000 kV three-phase power transformer according to a third embodiment of the present invention for detecting a low-energy series current transformer of a 1-1000 KV transformer;

Fig. 5 is a circuit diagram showing the fourth embodiment of the low-energy series current transformer for detecting a 1-1000 kV transformer of the present invention for three-phase current detection of the primary side of a 1-1000 kV three-phase power transformer. detailed description

'Following the drawings and specific examples for further explanation - Embodiment 1, as shown in Figure 1-2, the present invention detects a low-energy series current transformer of 1-1000KV transformer according to high-voltage line measurement, measurement and protection, etc. Required to select the number of winding cores, generally selected as

2 to 6 winding cores. According to the voltage level and primary rated current, select the voltage level, wire diameter, type and number of turns of the high-voltage insulated single-core cable for the busbar. The primary through-core busbar can be selected one or two turns, depending on the ratio and cable. According to the technical parameters, when it is two turns, it is generally set to be connected in series or parallel to obtain two current ratios; then the cross-sectional area of the iron core and the wire diameter of the secondary coil are designed according to the secondary rated current and the ratio. Number of turns. In the figure, the transformer end of the primary through-core bus is P1, and the output power line end is P2.

In the production, the iron core is first insulated with paper, and then the secondary winding coil is layered and insulated for insulation, and the secondary winding terminal is sequentially taken out and then cast. For a single-core high-voltage insulated single-core cable, first take out a small piece of copper conductor and set the terminal structure, then carry out cable head treatment to prevent leakage of insulating oil and moisture gas. The treated primary through-core busbar is threaded into the core in a forward direction and then cast into a closed or semi-closed structure.

The 10-1000kV series low-energy environment-friendly current transformer of the invention can be divided into four types according to the shape of the primary winding, such as a chain structure, an upright suspension ring structure, an inverted lifting ring structure and a U-shaped structure. Among them, the vertical hanging ring type structure and the u-shaped structure are long in one winding, consume more cables, and have relatively high cost, while the inverted hanging ring structure consumes less cables and the cost is relatively low, depending on the specific situation.

Embodiment 2 As shown in FIG. 2, the low-energy series current transformer for detecting 1-1000KV transformer of the present invention is a bus-through core current transformer, which comprises a core 1, a primary coil 2, a secondary coil 3, and two The secondary coil 3 is connected in series with the ammeter 5 and the voltmeter 4 in parallel, one end of the ammeter 5 and the voltmeter 4 is connected to the third end of the secondary coil through the two-position switch 7, and the other end of the ammeter 5 and the voltmeter 4 is passed through the wire and the second The other end of the coil 3 is connected. One end of the two-position switch 7 is connected to the fifth end of the ammeter and the third end of the secondary coil, and the other end of the two-position switch 7 is such that one end of the voltmeter 4 is connected to the 3-terminal of the secondary coil. Detect the current of any phase of the 1-75 million volt transformer. Embodiment 3 As shown in FIG. 3, the low-energy series current transformer for detecting 1-1000KV transformer of the present invention has the following technical features in addition to the technical features described in FIG. 1, namely: the current transformer It is a single-turn busbar core type, LM:, LMK, LMZ, LMZ, LMZJ, LMZJ, six new types of current transformers; primary coil series three-phase power transformer neutral. In the figure, AO, BO, CO and ground are the traditional three-phase four-wire power supply, D is the end of the three-phase winding and the ground connection; AO, BO, and CO are the secondary windings of the three-phase transformer. The three-phase four-wire system is also used for power supply. This figure is a schematic diagram of three-phase current detection of the primary side of a 1-75-megavolt three-phase power transformer using six types of bus-through current-carrying current transformers. The live line of the three-phase power transformer, the neutral line is a series circuit, the current intensity of the series circuit is the same, so the detection current from the hot line end has the same function as the detection current from the zero line end. Among them: TA2, TA3 and TA1 are the same wiring, they are all current transformers.

Embodiment 4 As shown in FIG. 4, the low-energy series current transformer for detecting 1-1000KV transformer of the present invention is a busbar core-type current transformer, which comprises a core 1, a primary coil 2, a secondary coil 3, and two The secondary coil 3 is connected to the current coil 41 of the meter 4, and the voltage coil 42 of the meter 4 is connected to the 220V or 380V line. It can be used to sense the current of any phase of a 1-000KV transformer. The current transformer is a single-turn busbar core type, LMK, LMKi, LMZ, LMZ LMZJ, LMZJ, six new types of current transformers; one-phase coil series three-phase power transformer neutral line. In the figure, AO, BO, CO and ground are the traditional three-phase four-wire power supply, D is the end of the three-phase winding and the ground connection; AO, BO, and CO are the secondary windings of the three-phase transformer. The three-phase four-wire system is also used for power supply. This figure is a schematic diagram of three-phase current detection of the primary side of a 1-1000 V three-phase power transformer using six types of bus-through current-carrying current transformers. The live line of the three-phase power transformer, the neutral line is a series circuit, and the current strength of the series circuit is the same, so detecting the current from the live line has the same function as detecting the current from the neutral line. Among them: TA2, TA3 and TA1 are the same wiring, they are current transformers.

The research group selected LMK, LMKi, LMZ, LMZ^ LMZJ, LMZJ, six new types of current transformers. The secondary open circuit voltage from 150 / 5 to 2000 / 5 is only 2.85 to 36V, and the primary voltage drop is equal to 0.093V to 0.09V. between. The low-voltage current transformer can be modified and connected to the neutral line of 10KV, 35KV, 110KV, 220V, 500KV, 750KV power transformers, and the application of the relevant watt-hour meter and the voltage coil of the watt-hour meter are still implemented according to the traditional process; The detected current and voltage are equal to the actual watt-hour meter, and the voltmeter reading is multiplied by the ratio. TA2, TA3 and TA1 are single-turn busbar-type current transformers, among which are LMK, LMK, LMZ, LMZ, LMZJ, LMZJ, and six types of 150/5~2000/5 TA. If needed The small change ratio can be achieved by changing the number of penetrating hearts by 150/5, 200/5. The monthly end value of the meter is multiplied by the ratio of TA to the end of the month. The meter and voltage coil are still operated in a conventional process.

The primary transformers of the current transformers are connected in parallel, and the secondary coils are connected in series to increase the ratio, thereby improving the flexibility of product design.

The energy-saving percentage analysis of the low-energy series current transformer (hereinafter referred to as TA) applied to the 1-75 million-volt power transformer of the present invention - the measured voltage drop of the low-energy current transformer 30/5TA of the present invention is 0.093V, the secondary rating The current is 30A and its primary power loss is 0.093 x 30 = 2.79 2.8 (W).

For the original 30/5TA, the voltage drop is 2.56V, and the secondary current is 30A. The corresponding primary power loss is: 2.12x30=63.6 (W) _c

Percentage of energy savings: (63.6-2.8) ÷63.6χ 100%-96%.

For the low-energy current transformer of the present invention, the measured voltage drop is 0.09V in 2000/5, and the secondary rated current is 2000Α, which corresponds to a primary power loss of 0.09 x 2000=180 (W).

For the original 2000/5TA, the voltage drop was 0.21V, and the secondary current was 2000A. The corresponding primary power loss was 0.21 x 2000=420 (W).

Percentage of energy savings: (420-180) ÷420x l00°/c^57.14%.

In summary: Compared with the traditional current transformer, the low-energy series current transformer of the invention has an energy saving range of 57% to 96%, has obvious objective energy-saving effect, and has significant social and economic benefits.

According to the traditional linear theory, the primary coil of the traditional TA is connected in series with the three live wires of the transmission and distribution line (ie, the hot-wire type TA). The technical difficulties and requirements of the design are: to prevent the heating of the TA induction coil from burning or high-voltage breakdown, thus the traditional In the design of the upper layer of TA, the use of oil immersion or sulfur hexafluoride gas-type insulation cooling structure, resulting in the traditional TA "three differences and three major difficulties" defects, that is, poor precision, poor safety, poor reliability, energy consumption, Large size, large consumables, difficult to install, and difficult to maintain. Using the TA nonlinear theory and the TA designed by its own patented technology, it realizes the low-voltage measurement equivalent replacement high-voltage measurement, which has the advantages of "three highs, three small two easy", namely high precision, high safety, high reliability and low energy consumption. Small size, low consumables, easy installation and easy maintenance.

Compared with the traditional TA, it has five advantages: The first is energy saving and emission reduction. According to the energy consumption comparison test of the TA ratio of 30/5 to 2000/5 and 10kV, the TA of the same ratio is better than the traditional TA. The consumption is reduced by 57%~96%. According to the 2007 China TA usage scale survey, based on the characteristics of the project itself, it is predicted to replace the existing products and can occupy 50% of the market. It can reduce about 5 billion kWh, which is equivalent to saving 1.75 million tons of standard coal, correspondingly reducing emissions of 4.605 million tons of CO2 and 27,600 tons of S02. The second is to save natural resources. Compared with traditional TA, this TA saves raw materials. More than 50%, for example, the traditional TA weight of a 500,000 volt substation is 5.09 tons, and the weight of the TA is less than 0.5 tons. The third is to save construction investment. The traditional TA is large in size, heavy in weight, high in price, and construction and installation. The cost is high, and the project TA is small in size, light in weight, low in price, low in construction and installation engineering, and all of the high-voltage insulators used in traditional TA are eliminated, reducing investment; the fourth is safe and maintenance-free, traditional TA installation. On the three live lines of the transmission and distribution lines, high-voltage operation poses a threat to personal safety, and the TA of this project is installed in the neutral line of the power transformer, which realizes low-voltage measurement, low-voltage operation, no high-voltage danger and threat to personal safety, and is connected to the zero line type. TA can be maintenance-free, thereby reducing operating costs and the impact of maintenance and repairs on power generation and production; Fifth, environmental protection, this item The energy used by TA is electric power. The material composition is copper wire, epoxy resin and other raw materials. It replaces the original cooling insulating oil, sulfur hexafluoride gas and other insulating materials that are easy to produce pollution and toxic, cancels the pollution source, and truly achieves green. Environmental protection.

Claims

Claim

1. A low-energy series current transformer for detecting 1-1000KV transformers, which is a busbar core-type current transformer, which comprises an iron core, a primary coil and a secondary coil, and is characterized in that a series of high-voltage insulated cables of 10~1000kV are used. Make a heart-through bus.

2. A low energy series current transformer for detecting a 1-1000 KV transformer according to claim 1, characterized in that the secondary coil is connected to a current coil of a power meter.

3. A low-energy series current transformer for detecting a 1-1000 kV transformer according to claim 2, wherein the voltage coil of the watt-hour meter is connected to a 220V or 380V line.

4. The low-energy series current transformer for detecting 1-1000KV transformer according to claim 1, characterized in that the secondary coil is connected in series with an ammeter and a voltmeter, and one end of the ammeter and the voltmeter are passed through the two-position switch and the second One end of the coil is connected, and the other end of the ammeter and the voltmeter is connected to the other end of the secondary coil through a wire.

5. The low-energy series current transformer for detecting a 1-1000 KV transformer according to claim 4, wherein one end of the two-position switch is such that one end of the ammeter is connected to one end of the secondary coil, and the other end of the two-position switch is a voltage. One end of the table is connected to one end of the secondary coil.

6. The low-energy series current transformer for detecting 1-1000KV transformer according to claim 1, characterized in that the high-voltage insulated cable adopts single-core or three-core or multi-core cable, and the cable insulation form adopts polyethylene cross-linked insulation. , or self-contained oil-filled paper insulation.

7. A low-energy series current transformer for detecting a 1-1000 KV transformer according to claim 1 or 2 or 3 or 4 or 5 or 6, wherein said current transformer is a single-turn busbar core type, LMK, LMK^ LMZ, LMZ! LMZJ, LMZJ, six series of new current transformers; primary coil series three-phase power transformer fire line or primary coil series three-phase power transformer zero line.

8. A low-energy series current transformer for detecting a 1-1000 KV transformer according to claim 1 or 2 or 3 or 4 or 5 or 6, wherein said current transformer is a single-turn busbar core type, LMK, LMK, LMZ, LM, LMZJ, LMZJ, six series of new current transformers; the live and neutral wires of the power transformer are respectively connected to the current sensor, and the high-voltage insulated cable is used as the primary wire of the primary bus three-phase power transformer, the copper wire, copper The wire acts as a zero-line of the three-phase power transformer of the primary bus of the primary coil.