On-load tap-changer and control method and control device thereof

Abstract

The invention discloses an on-load tap-changer and a control method and device thereof. The on-load tap-changer comprises an on-load tap-changer body and a control module. The on-load tap-changer body comprises a contact loop and at least one transition resistor branch, the transition resistor branch is formed by connecting a transition resistor and a current measurement module in series, and the transition resistor branch is connected in an electrical loop of the contact loop in series; the control module receives the transition resistor current sampling value sent by the current measuring module, the energy accumulation value of the transition resistor in the fixed time is obtained through integral operation, and when the energy accumulation value is larger than a fixed value, the control device outputs an over-energy protection action warning signal. A current measurement module is additionally arranged on a transition resistor branch, a transition resistor current sampling value is transmitted to a control module outside the on-load tap-changer, transition resistor over-energy protection is configured through integral operation of the resistor current sampling value, and a winding inter-stage short circuit fault and a sliding gear fault passing through a transition resistor are recognized and judged.

Description

Technical Field

[0001] The invention belongs to the field of high-voltage direct current power transmission, and in particular relates to an on-load tap changer and a control method and a control device thereof. Background Art

[0002] The main function of the on-load tap changer is to achieve transformer voltage regulation. The on-load tap changer (hereinafter referred to as OLTC) of the converter transformer in the UHV DC transmission project has a worse operating condition than that of ordinary power transformers. The reasons are: 1. The converter transformer operates at full load for a long time, and the current flowing through the OLTC is large; 2. The load current flowing through the on-load tap changer of the converter transformer is not a sine wave, but a current waveform with a phase change process. The di / dt of the zero crossing point is large, and it is difficult to extinguish the arc; 3. The converter transformer OLTC operates very frequently, and the number of operations during operation can reach 4,000 times / year, and the mechanical life requirement is high; 4. Frequent gear adjustment can easily cause changes in the mechanical and electrical characteristics of the relays and travel switches used in the electric mechanism control circuit.

[0003] The above differences are the main factors that cause two types of faults in the on-load tapchanger of the converter transformer. One type of fault is the internal fault of the on-load tapchanger that causes a short circuit between the transformer voltage regulating winding stages, and the other type of fault is the slip fault of the electric mechanism that causes the on-load tapchanger to continuously adjust the gears. Both types of faults lack effective and rapid identification and protection. Since the on-load tapchanger is installed inside the transformer, a significant manifestation of the continued fault is the continuous abnormal heating of the transition resistor, which causes the oil chamber inside the transformer to overheat, followed by a fire and explosion, causing the entire transformer to burn out, with serious consequences.

[0004] In view of the above problems, in some solutions of the prior art, since the short-circuit fault between transformer stages cannot be identified through the electrical quantity protection of the transformer itself, it can only be judged through the transformer oil temperature non-electrical quantity protection. The protection judgment time is too long and direct, fast and effective protection cannot be performed.

[0005] In response to the above problems, in some solutions of the prior art, the judgment of the electric mechanism gear slip fault is still made indirectly through the time relay inside the electric mechanism. The principle is that after the electric mechanism has undergone multiple continuous gear adjustments, the time relay is activated to judge that a gear slip fault has occurred. The fault judgment time takes at least tens of seconds, and the judgment basis is indirect and the time is too long. Summary of the invention

[0006] The purpose of the present invention is to provide an on-load tap changer and a control method and a control device thereof. By adding a current measurement module to a transition resistor branch, the transition resistor current sampling value of the current measurement module is transmitted to a control module outside the on-load tap changer. Through the integral operation of the resistor current sampling value, a transition resistor over-energy protection is configured to identify and judge the inter-stage short-circuit fault and the slip fault of the winding through the transition resistor.

[0007] In order to achieve the above object, the solution of the present invention is:

[0008] An on-load tap changer comprises an on-load tap changer body and a control module; wherein the on-load tap changer body comprises a contact circuit and at least one transition resistance branch, the transition resistance branch is composed of a transition resistance and a current measurement module connected in series, and the transition resistance branch is connected in series in an electrical circuit of the contact circuit; the control module outputs a transition resistance over-energy protection action alarm signal according to transition resistance current sampling data I collected by the current measurement module.

[0009] The contact circuit comprises a first contact, a second contact and a third contact, wherein one end of the first contact is a tap input a terminal of the on-load tap changer body, one end of the third contact is connected to one end of the transition resistance branch as a tap input b terminal of the on-load tap changer body, one end of the second contact is connected to the other end of the transition resistance branch, and the other ends of the first, second and third contacts are commonly connected as a tap output c terminal of the on-load tap changer body.

[0010] The contact circuit comprises a fourth contact, a fifth contact, a sixth contact and a seventh contact, and the on-load tap changer body comprises two transition resistance branches; wherein, one end of the fourth contact is connected to one end of the first transition resistance branch as a tap input terminal a of the on-load tap changer body, one end of the seventh contact is connected to one end of the second transition resistance branch as a tap input terminal b of the on-load tap changer body, one end of the fifth contact is connected to the other end of the first transition resistance branch, one end of the sixth contact is connected to the other end of the second transition resistance branch, and the other ends of the fourth, fifth, sixth and seventh contacts are commonly connected to the tap output terminal c of the on-load tap changer body.

[0011] The contact circuit includes an eighth contact, a ninth contact, a tenth contact, an eleventh contact, a twelfth contact, a thirteenth contact, a fourteenth contact and a fifteenth contact, and the on-load tap changer body includes two transition resistance branches; wherein, one end of the eighth contact is connected to one end of the tenth contact as a tap input a end of the on-load tap changer body, the other end of the eighth contact is connected to one end of the ninth contact, the other end of the tenth contact is respectively connected to one end of the eleventh contact and one end of the first transition resistance branch, one end of the twelfth contact is connected to one end of the fourteenth contact as a tap input b end of the on-load tap changer body, the other end of the twelfth contact is connected to one end of the thirteenth contact, and the other end of the fourteenth contact is respectively connected to one end of the fifteenth contact and one end of the second transition resistance branch; the other ends of the ninth contact, the eleventh contact, the first transition branch, the thirteenth contact, the fifteenth contact and the second transition branch are commonly connected to a tap output c end of the on-load tap changer body.

[0012] The control module is equipped with an optical fiber communication interface to transmit the action alarm signal.

[0013] As described above, in a control method for an on-load tap changer, after the control module receives the transition resistor current sampling data I collected by the current measurement module, the control module performs a power measurement on the transition resistor I 2 R performs integration operation within a fixed period T to obtain the transition resistance energy accumulation value E. When the energy accumulation value E exceeds the maximum energy setting value Emax, the control module outputs a transition resistance over-energy protection action alarm signal.

[0014] A control device for an on-load tap changer as described above comprises:

[0015] A current measurement module is used to collect transition resistance current sampling data I;

[0016] The integral operation module is used to calculate the transition resistance power I within a fixed period T according to the transition resistance current sampling data I 2 R is integrated to obtain the cumulative value of transition resistance energy E;

[0017] A judgment module, used for comparing the transition resistance energy accumulation value E with the maximum energy setting value Emax, and outputting a signal to the output alarm module if E exceeds Emax; and

[0018] The output alarm module is used to output a transition resistance over-energy protection action alarm signal according to the output signal of the judgment module.

[0019] After adopting the above scheme, the present invention can configure a current measurement module through a transition resistance branch of the proposed on-load tap changer, and configure a control module to perform an integral operation on the collected current to obtain the transition resistance energy, so as to realize the transition resistance over-energy protection function, and has the following beneficial effects:

[0020] (1) Conventional transformer voltage regulating winding interstage short circuit non-electrical quantity protection. In the case of transition resistor short circuit, the fault can be judged by transition resistor over-energy protection, and the long-time and indirect non-electrical quantity protection can be replaced by direct electrical quantity fast protection.

[0021] (2) For the gear slip fault caused by the change of the characteristics of the internal relay and travel switch of the on-load tap changer motor mechanism, the over-energy of the transition resistor can be compared with the single gear shifting energy. When the energy exceeds the single gear shifting energy, the gear slip fault can be identified in time and protection can be provided.

[0022] (3) For the converter transformer on-load tap changer in the DC project, the control module configured in the present invention can be configured with an optical fiber communication interface between the DC control system. Compared with the cable node signal of the conventional on-load tap changer electric mechanism box, the signal transmission is faster and more resistant to interference. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is a topological diagram of the on-load tap changer of the present invention;

[0024] Figure 2 This is a structural diagram of a first embodiment of the on-load tap changer body of the present invention;

[0025] Figure 3 It is a structural diagram of a second embodiment of the on-load tap changer body of the present invention;

[0026] Figure 4 It is a structural diagram of a third embodiment of the on-load tap changer body of the present invention;

[0027] Figure 5 It is a schematic diagram of the transition resistor over-energy protection principle of the present invention.

[0028] Reference numerals:

[0029] 100-On-load tap changer body;

[0030] 200-control module;

[0031] 110-contact circuit; 120-transition resistance branch;

[0032] 121-transition resistor; 122-current measurement module;

[0033] K1-first contact; K2-second contact; K3-third contact;

[0034] K4-fourth contact; K5-fifth contact; K6-sixth contact; K7-seventh contact;

[0035] K8-eighth contact; K9-ninth contact; K10-tenth contact; K11-eleventh contact;

[0036] K12-twelfth contact; K13-thirteenth contact; K14-fourteenth contact; K15-fifteenth contact. DETAILED DESCRIPTION

[0037] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the specific implementation of the technical scheme of the present application will be described in more detail and clearly in conjunction with the accompanying drawings and embodiments. However, the specific implementation and embodiments described below are only for the purpose of explanation, rather than for limitation of the present application. It only includes a part of the embodiments of the present application, rather than all the embodiments, and other embodiments obtained by those skilled in the art for various changes of the present application belong to the scope of protection of the present application.

[0038] In the description of the present disclosure, it should be understood that the orientation or positional relationship indicated by the terms "upper" and "lower" and the like is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present disclosure and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present disclosure. In addition, the terms "first" and "second" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, the features defined as "first" and "second" may explicitly or implicitly include one or more of the said features. In the description of the present disclosure, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

[0039] In the description of the present disclosure, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or can communicate with each other; it can be directly connected, or indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present disclosure can be understood according to specific circumstances.

[0040] The technical solution of the present invention will be described in detail below with reference to the accompanying drawings.

[0041] like Figure 1As shown, the present invention provides an on-load tap changer, including an on-load tap changer body 100 and a control module 200, wherein the on-load tap changer body 100 is composed of a contact circuit 110 and at least one transition resistance branch 120; the transition resistance branch 120 is composed of a transition resistor 121 and a current measurement module 122 connected in series, and the transition resistance branch 120 is connected in series in the electrical circuit of the contact circuit 110.

[0042] like Figure 2 , which is a first embodiment of the structure of the on-load tap changer body 100 of the on-load tap changer provided by the present invention, wherein a transition resistance branch 120 is included; the contact circuit 110 includes a first contact K1, a second contact K2 and a third contact K3, one end of the first contact K1 serves as a tap input a-end of the on-load tap changer body 100, one end of the third contact K3 is connected to one end of the transition resistance branch 120 and serves as a tap input b-end of the on-load tap changer body 100, one end of the second contact K2 is connected to the other end of the transition resistance branch 120, and the other ends of the first, second and third contacts are connected together and serve as a tap output c-end of the on-load tap changer body 100.

[0043] like Figure 3 , which is a second embodiment of the structure of the on-load tap changer body 100 in the on-load tap changer provided by the present invention, wherein two transition resistance branches 120 are included; the contact circuit 110 includes a fourth contact K4, a fifth contact K5, a sixth contact K6 and a seventh contact K7, one end of the fourth contact K4 is connected to one end of the first transition resistance branch 120, and serves as a tap input a end of the on-load tap changer body 100, one end of the seventh contact K7 is connected to one end of the second transition resistance branch 120, and serves as a tap input b end of the on-load tap changer body 100, one end of the fifth contact K5 is connected to the other end of the first transition resistance branch 120, one end of the sixth contact K6 is connected to the other end of the second transition resistance branch 120, and the other ends of the fourth, fifth, sixth and seventh contacts are connected together, and serve as a tap output c end of the on-load tap changer body 100.

[0044] like Figure 4, which is a third embodiment of the structure of the on-load tap changer body 100 of the on-load tap changer provided by the present invention, wherein two transition resistance branches 120 are included; the contact circuit 110 includes an eighth contact K8, a ninth contact K9, a tenth contact K10, an eleventh contact K11, a twelfth contact K12, a thirteenth contact K13, a fourteenth contact K14 and a fifteenth contact K15, one end of the eighth contact K8 is connected to one end of the tenth contact K10, as a tap input a end of the on-load tap changer body 100, the other end of the eighth contact K8 is connected to one end of the ninth contact K9, the other end of the tenth contact K10 is connected to one end of the eleventh contact K11, and the other end of the tenth contact K11 is connected to one end of the eleventh contact K12. , one end of the first transition resistance branch 120; one end of the twelfth contact K12 is connected to one end of the fourteenth contact K14, serving as the tap input b end of the on-load tap changer body 100, the other end of the twelfth contact K12 is connected to one end of the thirteenth contact K13, and the other end of the fourteenth contact K14 is respectively connected to one end of the fifteenth contact K15 and one end of the second transition resistance branch 120; the ninth contact K9, the eleventh contact K11, the first transition branch 120, the thirteenth contact K13, the fifteenth contact K15, and the other end of the second transition branch 120 are connected together, and serve as the tap output c end of the on-load tap changer body 100.

[0045] like Figure 5 As shown, the present invention also provides a control method for the above-mentioned on-load tap changer, wherein the current measuring module 122 collects the transition resistance current sampling data I of the line in real time and transmits it to the control module 200. After the control module 200 receives the transition resistance current sampling data I collected by the current measuring module 122, the control module 200 performs a control operation on the transition resistance power I 2 R performs integration operation in a fixed period T to obtain the transition resistance energy accumulation value E. When the energy accumulation value E exceeds the maximum energy setting value Emax, the control module 200 outputs a transition resistance over-energy protection action alarm signal. The control module 200 can be configured with an optical fiber communication interface to transmit the action alarm signal.

[0046] As a preferred embodiment of the present invention, at time t1, the control module 200 receives the transition resistor current sampling data I1 collected by the current measurement module 122, and obtains the transition resistor power I1 at this time. t1 2 R, and integrate the transition resistance power within a fixed period T (t1-T, t1) The cumulative value E1 of the transition resistance energy is obtained. If E1 < Emax, the control module 200 does not output an alarm signal and continues to monitor. When the time reaches t1 + Δt, at this time, the power of the transition resistance in the time period (t1 + Δt - T, t1 + Δt) is integrated to obtain the cumulative value E2 of the transition resistance energy at this time. If E2 > Emax, the control module 200 outputs an alarm signal for the over-energy protection action of the transition resistance.

[0047] The present invention also provides a control device for the aforementioned on-load tap-changer, including a current measurement module, an integration operation module, a judgment module, and an output alarm module. Among them, the current measurement module is used to collect the sampled data I of the transition resistance current and send the collected data to the integration operation module; the integration operation module is used to integrate the power I of the transition resistance according to the sampled data I of the transition resistance current within a fixed time period T 2 R to obtain the cumulative value E of the transition resistance energy and send the result to the judgment module; the judgment module compares E with the maximum energy setting value Emax. If E does not exceed Emax, no signal will be output; if E exceeds Emax, a signal will be output to the output alarm module, and the output alarm module outputs an alarm signal for the over-energy protection action of the transition resistance.

[0048] The above embodiments are only used to illustrate the technical idea of the present invention and cannot be used to limit the protection scope of the present invention. Those of ordinary skill in the art should understand that any modification or equivalent replacement of the specific implementation manners of the present invention without departing from the technical idea and scope proposed by the present invention should be covered by the scope of the claims of the present invention.

Claims

1. An on-load tap changer, characterized in that: The invention comprises an on-load tap changer body (100) and a control module (200); wherein the on-load tap changer body (100) comprises a contact circuit (110) and at least one transition resistance branch (120); the transition resistance branch (120) is composed of a transition resistance (121) and a current measurement module (122) connected in series; the transition resistance branch (120) is connected in series to the electrical circuit of the contact circuit 110; and the control module (200) outputs a transition resistance over-energy protection action alarm signal according to transition resistance current sampling data I collected by the current measurement module (122).

2. An on-load tap changer according to claim 1, characterized in that: The contact circuit (110) comprises a first contact (K1), a second contact (K2) and a third contact (K3), wherein one end of the first contact (K1) is a tap input a end of the on-load tap changer body 100, one end of the third contact (K3) is connected to one end of a transition resistance branch (120) to form a tap input b end of the on-load tap changer body (100), one end of the second contact (K2) is connected to the other end of the transition resistance branch (120), and the other ends of the first, second and third contacts are commonly connected to form a tap output c end of the on-load tap changer body (100).

3. The on-load tap changer according to claim 1, characterized in that: The contact circuit (110) comprises a fourth contact (K4), a fifth contact (K5), a sixth contact (K6) and a seventh contact (K7); the on-load tap changer body (100) comprises two transition resistance branches (120); wherein one end of the fourth contact (K4) is connected to one end of the first transition resistance branch (120) as a tap input end a of the on-load tap changer body (100); one end of the seventh contact (K7) is connected to one end of the second transition resistance branch (120) as a tap input end b of the on-load tap changer body (100); one end of the fifth contact (K5) is connected to the other end of the first transition resistance branch (120); one end of the sixth contact (K6) is connected to the other end of the second transition resistance branch (120); and the other ends of the fourth, fifth, sixth and seventh contacts are connected together as a tap output end c of the on-load tap changer body (100).

4. The on-load tap changer according to claim 1, characterized in that: The contact circuit (110) comprises an eighth contact (K8), a ninth contact (K9), a tenth contact (K10), an eleventh contact (K11), a twelfth contact (K12), a thirteenth contact (K13), a fourteenth contact (K14) and a fifteenth contact (K15); the on-load tap changer body (100) comprises two transition resistance branches (120); wherein one end of the eighth contact (K8) is connected to one end of the tenth contact (K10) as a tap input a end of the on-load tap changer body (100); the other end of the eighth contact (K8) is connected to one end of the ninth contact (K9); the other end of the tenth contact (K10) is connected to one end of the eleventh contact (K11), the first transition resistance branch (120) and the second transition resistance branch (120) respectively. The first transition resistance branch (120) is connected to one end of the ninth contact (K9), the eleventh contact (K11), the first transition branch (120), the thirteenth contact (K13), the fifteenth contact (K15) and the other end of the second transition branch (120) are connected together to form a tap output c end of the on-load tap changer body (100).

5. The on-load tap changer according to claim 1, characterized in that: The control module (200) is equipped with an optical fiber communication interface to transmit an action alarm signal.

6. A method for controlling an on-load tap changer according to any one of claims 1 to 5, characterized in that: After receiving the transition resistor current sampling data I collected by the current measurement module (122), the control module (200) measures the transition resistor power I 2 R performs an integral operation within a fixed period T to obtain a transition resistance energy accumulation value E. When the energy accumulation value E exceeds a maximum energy setting value Emax, the control module (200) outputs a transition resistance over-energy protection action alarm signal.

7. A control device for an on-load tap changer according to any one of claims 1 to 5, characterized in that: include, A current measurement module is used to collect transition resistance current sampling data I; The integral operation module is used to calculate the transition resistance power I within a fixed period T according to the transition resistance current sampling data I 2 R is integrated to obtain the cumulative value of transition resistance energy E; A judgment module, used for comparing the transition resistance energy accumulation value E with the maximum energy setting value Emax, and outputting a signal to the output alarm module if E exceeds Emax; and The output alarm module is used to output a transition resistance over-energy protection action alarm signal according to the output signal of the judgment module.

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