Self-coupling turn-adjusting capacitance-casting arc suppression coil

Abstract

The invention relates to a self-coupling turn-adjusting capacitance-throwing arc suppression coil which comprises a turn-adjusting arc suppression coil body, an on-load tap-changer, a capacitor and a capacitor switch. The arc suppression coil body is provided with a tap, and the tap is correspondingly connected with an on-load tap switch; and the capacitor switch and the capacitor are connected in series and then are connected to the X end of the arc suppression coil body and one tap, so that the self-coupling turn-adjusting capacitance-throwing arc suppression coil is formed. The current and the number of turns of each tap of the arc suppression coil body are determined through an increment equal difference method of the differential current, and the number of gears is reduced to the maximum extent while the differential current is ensured to be within a standard value. According to the self-coupling type turn-adjusting capacitance-throwing arc suppression coil, the number of taps led out of the arc suppression coil body is small, the number of gears of the on-load tap-changer is small, control is easy, the adjusting and switching range is wide and thin, and the operation safety of a system can be improved.

Description

Technical Field

[0001] The invention relates to the technical field of arc extinguishing coils, and in particular to a self-coupling type turn-adjusting and capacitance-throwing arc extinguishing coil. Background Art

[0002] With the continuous expansion of the scale of the power system, the increase in the length of the lines in the distribution system and the increase in the number of power cables, the capacitance of the distribution network to the ground has increased significantly, and the capacitance current value has become larger and larger. When a single-phase grounding occurs in the distribution network of the small current grounding system, the arc at the fault point may not be extinguished in time and effectively, which may cause the fault to expand, forming a disconnection fault or a permanent grounding fault, or more seriously, developing into a phase-to-phase short circuit fault. Therefore, the regulations stipulate that when the capacitance current of the single-phase grounding fault of the power grid exceeds a certain value, the neutral point must be installed with an arc suppression coil for grounding, so that the arc can be automatically extinguished quickly to prevent the fault from further expanding and ensure the safe and reliable operation of the power system.

[0003] Arc extinguishing coils are classified into turn-adjusting type, capacitance-adjusting type, phase-controlled type, DC bias magnetic type and air gap-adjusting type according to the inductance adjustment method. Among them, the turn-adjusting type arc extinguishing coil includes an arc extinguishing coil body and an on-load switch for adjusting the inductance value of the arc extinguishing coil body. The arc extinguishing coil body includes an iron core and a winding wound on the iron core, and the winding is provided with a number of taps corresponding to the number of on-load switch gears. Since the body of the arc extinguishing coil switches the winding taps through the on-load switch to adjust the inductance value of the system, it has the advantages of high reliability, no harmonic current, and fast compensation speed. However, during the use of the turn-adjusting type arc extinguishing coil, if the capacity is large and the current adjustment range is wide, due to the limitation of the number of on-load switch gears, the differential current will inevitably exceed the specified value of the industry standard, thereby failing to ensure reliable arc extinguishing. For example, the model XHDCZ-1000 / 10.5 has a current adjustment range of 51.9-163.3A, with a total of 19 levels, and an average differential current of 6.36A, which obviously exceeds the standard requirements of the power industry.

[0004] The implementation schemes provided by Chinese patents with application numbers of 2005101300517, 2008200489215, 2009202260826 and 2002202260826 have complex coil structures and controls. Chinese patent with application number of 2013105687858 connects the winding to the system through a first switch and a second switch connected in parallel, and can divide the winding into two sections with different total turns for adjustment respectively, from K1 closure to K2 closure or K2 closure to K1 closure, the reactance value of the arc extinguishing coil changes in leaps and bounds, affecting the safe operation of the system. Summary of the invention

[0005] The object of the present invention is to provide a self-coupling type turn-adjusting and capacitance-throwing arc-extinguishing coil, which has fewer taps led out from the arc-extinguishing coil body, fewer on-load tap changer gears, simple control, wide and fine adjustment range, and can improve the safety of system operation.

[0006] In order to achieve the above-mentioned purpose, the technical solution adopted by the present invention is: a self-coupling type turn-adjusting and capacitance-throwing arc-extinguishing coil, comprising a turn-adjusting arc-extinguishing coil body, an on-load tap changer, a capacitor and a capacitor switch; the arc-extinguishing coil body is provided with a tap, and the tap is correspondingly connected to the on-load tap changer; the capacitor switch is connected in series with the capacitor and then connected to the X end of the arc-extinguishing coil body and a tap, forming a self-coupling type turn-adjusting and capacitance-throwing arc-extinguishing coil.

[0007] Furthermore, the tap of the arc extinguishing coil body is correspondingly connected to the on-load tap changer to form gears 1 to N, and the capacitor is put into operation to form corresponding gears 1C to NC, so that the arc extinguishing coil forms a compensation current of 2N gears.

[0008] Furthermore, the compensation current adjustment method of the auto-coupling type turn-adjusting and capacitor-throwing arc-extinguishing coil is: directly adjusting from the m position to the m+1 position through the on-load tap changer; adjusting from the m position to the m+1 position through the on-load tap changer and inputting the capacitor through the capacitor switch to obtain the (m+1)C position.

[0009] Furthermore, the method for selecting the capacitor capacity is: after the capacitor is put into operation, the compensation current difference of the arc suppression coil is smaller than the standard value.

[0010] Furthermore, the capacitor switch is connected in series with the capacitor and is connected to the X end of the arc extinguishing coil body and a tap closest to the X end to form a self-coupling type turn-adjusting and capacitance-throwing arc extinguishing coil.

[0011] Furthermore, the current and the number of turns of each tap of the arc extinguishing coil body are determined by the incremental arithmetic difference method of the differential current, including the following steps:

[0012] ① Calculate and determine the number of gears of the arc extinguishing coil according to the following formula:

[0013]

[0014] Among them, I N is the current of the maximum gear N of the arc extinguishing coil body tap; I1 is the current of the minimum gear 1 of the arc extinguishing coil body tap; ΔI m I is the maximum differential current of the arc extinguishing coil from position m to position (m+1)C; CN I is the capacitance compensation current of the capacitor in the N position of the auto-coupling type turn-adjusting arc-extinguishing coil; C1 The capacitance compensation current of the capacitor in the first gear of the auto-coupling type turn-adjusting arc-extinguishing coil; It means to round up the calculation result to the nearest odd number.

[0015] ② According to the number of gears N determined in step ①, calculate the differential current of the arc extinguishing coil from gear m to gear (m+1)C:

[0016]

[0017] ③ According to the number of gears N determined in step ①, calculate the incremental differential value of the differential current of the arc extinguishing coil body tap:

[0018]

[0019] ④Calculate the current of m gear according to steps ①, ②, and ③:

[0020]

[0021] ⑤ According to the current of the m-level calculated in step ④, calculate the number of tap turns of the m-level:

[0022]

[0023] Among them, W m is the number of tap turns in gear m, W N is the number of tap turns in N gear.

[0024] Compared with the prior art, the present invention has the following beneficial effects: the present invention provides a self-coupling type turn-adjusting and capacitance-changing arc-extinguishing coil. In the absence of a secondary coil, the arc-extinguishing coil of the same on-load tap changer can double its actual gear position by adding capacitor switching, with fewer components, simple control, reliable operation, a relatively wide current regulation range, and relatively fine regulation, which is beneficial to the control of residual current. When a new large-capacity arc-extinguishing coil is manufactured, the number of gears of the on-load tap changer and the number of taps of the arc-extinguishing coil body can be reduced. For the arc-extinguishing coil in operation, if the differential current is greater than the specification value, the residual current can meet the specification requirements after adding capacitor switching, which is convenient for on-site modification. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a structural schematic diagram of a self-coupling type turn-adjusting and capacitance-throwing arc-extinguishing coil according to an embodiment of the present invention. DETAILED DESCRIPTION

[0026] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0027] It should be noted that the following detailed descriptions are exemplary and are intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present application belongs.

[0028] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0029] This embodiment provides a self-coupling type turn-adjusting and capacitance-casting arc-extinguishing coil, comprising a turn-adjusting arc-extinguishing coil body, an on-load tap changer, a capacitor and a capacitor switch. The arc-extinguishing coil body is provided with a tap, and the tap is correspondingly connected to the on-load tap changer. The capacitor switch is connected in series with the capacitor to the X end of the arc-extinguishing coil body and a tap closest to the X end, forming a self-coupling type turn-adjusting and capacitance-casting arc-extinguishing coil.

[0030] The tap of the arc extinguishing coil body is connected to the on-load tap changer to form gears 1 to N, and the capacitor is put into operation to form corresponding gears 1C to NC, so that the arc extinguishing coil forms a compensation current of gear 2N.

[0031] The auto-coupling type turn-adjusting and capacitor-throwing arc-extinguishing coil only needs one arc-extinguishing coil body, and no secondary coil is required. The 2N-level compensation current is formed by switching the capacitor through the N-level on-load tap changer and the capacitor switch, and the actual level is doubled. It has few components, simple control, reliable operation, a wide current regulation range, and fine regulation, which is conducive to the control of residual current. It can reduce the number of levels of the on-load tap changer and the number of taps of the arc-extinguishing coil body.

[0032] For arc suppression coils in operation, if the differential current is greater than the specification value (5A), adding capacitors can make the residual current meet the specification requirements, which is convenient for on-site modification; when manufacturing new large-capacity arc suppression coils, the number of on-load tap changer gears and the number of taps of the arc suppression coil body can be reduced.

[0033] The compensation current adjustment method of the auto-coupling type turn-adjusting and capacitor-throwing arc-extinguishing coil is: directly adjusting from the m position to the m+1 position through the on-load tap changer; adjusting from the m position to the m+1 position through the on-load tap changer and inputting the capacitor through the capacitor switch to obtain the (m+1)C position.

[0034] The method for selecting the capacitor capacity is as follows: after the capacitor is put into operation, the compensation current difference of the arc suppression coil is less than the standard value.

[0035] In this embodiment, the current and number of turns of each tap of the arc suppression coil body are determined by the incremental arithmetic difference method of the differential current, and the number of gears is minimized to the greatest extent while ensuring that the differential current is within the standard value; specifically, the following steps are included:

[0036] ① Calculate and determine the number of gears of the arc extinguishing coil according to the following formula:

[0037]

[0038] Among them, I N is the current of the maximum gear N of the arc extinguishing coil body tap; I1 is the current of the minimum gear 1 of the arc extinguishing coil body tap; ΔI m I is the maximum differential current of the arc extinguishing coil from level m to level (m+1)C (e.g. level 1 to level 2C); CN I is the capacitance compensation current of the capacitor in the N position of the auto-coupling type turn-adjusting arc-extinguishing coil; C1 The capacitance compensation current of the capacitor in the first gear of the auto-coupling type turn-adjusting arc-extinguishing coil; It means to round up the calculation result to the nearest odd number, that is, N is the odd number rounded up based on the calculation result of the above formula.

[0039] ② According to the number of gears N determined in step ①, calculate the differential current of the arc extinguishing coil from gear m to gear (m+1)C:

[0040]

[0041] ③ According to the number of gears N determined in step ①, calculate the incremental differential value of the differential current of the arc extinguishing coil body tap:

[0042]

[0043] ④Calculate the current of m gear according to steps ①, ②, and ③:

[0044]

[0045] ⑤ According to the current of the m-level calculated in step ④, calculate the number of tap turns of the m-level:

[0046]

[0047] Among them, W m is the number of tap turns in gear m, W N is the number of tap turns in N gear. Specific embodiment one:

[0049] like Figure 1As shown in the figure, an arc extinguishing coil XHDCZ-1000 / 10.5 is in operation. The left coil of the arc extinguishing coil body is provided with A2, A4, A6, A8, A10, A12, A14, A16, A18, A20 taps, and the right coil of the arc extinguishing coil body is provided with A3, A5, A7, A9, A11, A13, A15, A17, A19, A21 taps. The taps are connected with the on-load tap changer to form a total of 19 levels of compensation current; a switch K is added to the arc extinguishing coil and a capacitor C with C = 10.6μF is connected in series and then connected in parallel to the X end of the arc extinguishing coil body and the A21 tap to form a self-coupling type turn-adjusting and capacitance-throwing arc extinguishing coil; the arc extinguishing coil body and the taps are connected to form 1 to 19 levels, and capacitors are added and closed with switch K to form corresponding 1C to 19C levels. The compensation current of the arc extinguishing coil has a total of 38 levels, as shown in Table 1.

[0050] Table 1 Compensation current table before and after the capacitor of the auto-coupling type turn-adjusting arc-extinguishing coil is put into operation

[0051]

[0052]

[0053] Specifically, if you want to adjust the compensation current of the arc suppression coil from 51.9A in level 1 to 56.8A in level 2C, just adjust the on-load tap changer from level 1 to level 2 and put in capacitor C; if you want to adjust the compensation current of the arc suppression coil from 51.9A to 58.6A, just adjust the on-load tap changer from level 1 to level 2; the rest are similar. Specific embodiment 2

[0055] One arc suppression coil XHDCZ-1000 / 10.5, maximum gear I N =166.3A,W N =321 turns; minimum gear I1 = 51.9A, W1 = 575 turns; Ue = 6062V, of which the number of turns between the X end and the tap closest to the X end is 160 turns. The capacitance compensation current of the arc extinguishing coil capacitor at the maximum gear is 5A. The total gear of the arc extinguishing coil and the current of the corresponding gear and the number of turns of each tap are analyzed as follows:

[0056] ① Selection of the number of gears for arc suppression coil:

[0057] The capacitance compensation current of the arc suppression coil capacitor in the 1st gear is:

[0058]

[0059] Number of gears:

[0060]

[0061] I N--The current of the arc suppression coil at the maximum gear N;

[0062] I1--the current of the arc suppression coil at the minimum gear 1;

[0063] △I m --The maximum differential current of the arc extinguishing coil from position m to position (m+1)C is 5A;

[0064] I CN --The capacitance compensation current of the capacitor of the auto-coupling type turn-adjusting arc-extinguishing coil in the N position is 5A;

[0065] I C1 --Capacitance compensation current of the auto-coupling type turn-adjusting arc-extinguishing coil capacitor in the first gear;

[0066] N is 15.

[0067] ② According to the 15 levels selected in step ①, calculate the differential current of the arc extinguishing coil from level m to level (m+1)C:

[0068]

[0069] ③ According to the 15th level selected in step ①, calculate the incremental differential value of the differential current of the arc suppression coil body tap:

[0070]

[0071] ④ Calculate the current of the mth gear according to steps ①, ②, and ③, such as the 5th gear:

[0072]

[0073] ⑤ According to the current of each gear calculated in step ④, calculate the number of tap turns of each gear:

[0074]

[0075] The calculation results are shown in Table 2.

[0076] Table 2 Compensation current table before and after the capacitor of the auto-coupling type turn-adjusting arc-extinguishing coil is put into operation using the incremental arithmetic difference method of differential current.

[0077]

[0078]

[0079] The above is only a preferred embodiment of the present invention, and does not limit the present invention in other forms. Any technician familiar with the profession may use the above disclosed technical content to change or modify it into an equivalent embodiment with equivalent changes. However, any simple modification, equivalent change and modification made to the above embodiment according to the technical essence of the present invention without departing from the technical solution of the present invention still belongs to the protection scope of the technical solution of the present invention.

Claims

1. A self-coupling type turn-adjusting and capacitance-throwing arc-extinguishing coil, characterized in that: It includes a turn-adjusting arc-extinguishing coil body, an on-load tap changer, a capacitor and a capacitor switch; the arc-extinguishing coil body is provided with a tap, and the tap is correspondingly connected to the on-load tap changer; the capacitor switch is connected in series with the capacitor and then connected to the X end of the arc-extinguishing coil body and a tap, forming a self-coupling turn-adjusting capacitor arc-extinguishing coil.

2. The self-coupling type turn-adjusting and capacitance-throwing arc-extinguishing coil according to claim 1 is characterized in that: The tap of the arc extinguishing coil body is connected to the on-load tap changer to form gears 1 to N, and the capacitor is put into operation to form corresponding gears 1C to NC, so that the arc extinguishing coil forms a compensation current of gear 2N.

3. The self-coupling type turn-adjusting and capacitance-throwing arc-extinguishing coil according to claim 2 is characterized in that: The compensation current adjustment method of the auto-coupling type turn-adjusting and capacitor-throwing arc-extinguishing coil is: directly adjusting from the m position to the m+1 position through the on-load tap changer; adjusting from the m position to the m+1 position through the on-load tap changer and inputting the capacitor through the capacitor switch to obtain the (m+1)C position.

4. The self-coupling type turn-adjusting and capacitance-throwing arc-extinguishing coil according to claim 2 is characterized in that: The method for selecting the capacitor capacity is as follows: after the capacitor is put into operation, the compensation current difference of the arc suppression coil is less than the standard value.

5. The self-coupling type turn-adjusting and capacitance-throwing arc-extinguishing coil according to claim 1 is characterized in that: The capacitor switch is connected in series with the capacitor and is connected to the X end of the arc extinguishing coil body and a tap closest to the X end to form a self-coupling type turn-adjusting and capacitance-throwing arc extinguishing coil.

6. The self-coupling type turn-adjusting and capacitance-throwing arc-extinguishing coil according to claim 1, characterized in that: The current and number of turns of each tap of the arc extinguishing coil body are determined by the incremental arithmetic difference method of the differential current, including the following steps: ① Calculate and determine the number of gears of the arc extinguishing coil according to the following formula: Among them, I N is the current of the maximum gear N of the arc extinguishing coil body tap; I1 is the current of the minimum gear 1 of the arc extinguishing coil body tap; ΔI m I is the maximum differential current of the arc extinguishing coil from position m to position (m+1)C; CN I is the capacitance compensation current of the capacitor in the N position of the auto-coupling type turn-adjusting arc-extinguishing coil; C1 The capacitance compensation current of the capacitor in the first gear of the auto-coupling type turn-adjusting arc-extinguishing coil; It means to round up the calculation result to the nearest odd number. ② According to the number of gears N determined in step ①, calculate the differential current of the arc extinguishing coil from gear m to gear (m+1)C: ③ According to the number of gears N determined in step ①, calculate the incremental differential value of the differential current of the arc extinguishing coil body tap: ④Calculate the current of m gear according to steps ①, ②, and ③: ⑤ According to the current of the m-level calculated in step ④, calculate the number of tap turns of the m-level: Among them, W m is the number of tap turns in gear m, W N is the number of tap turns in N gear.

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