Thyristor mechanical hybrid switching circuit
By designing a thyristor-mechanical hybrid switching circuit, the thyristor is triggered to conduct using the break voltage, which solves the problem of arcing during the switching process of on-load tap changers, improves electrical life, and reduces maintenance costs.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-27
- Publication Date
- 2026-03-31
AI Technical Summary
Existing on-load tap changers generate electric arcs during switching, resulting in energy loss and contact burnout, affecting electrical life and incurring high maintenance costs.
A thyristor-mechanical hybrid switching circuit is adopted. By combining thyristor modules and vacuum tube pairs, arc-free switching is achieved. The thyristor conduction is triggered by the break voltage, thus avoiding the generation of mechanical break arc.
Arc-free switching was achieved, which improved the electrical life of on-load tap changers and reduced maintenance costs.
Smart Images
Figure CN224067578U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of on-load tap changer switching circuit technology, specifically to a thyristor-mechanical hybrid switching circuit. Background Technology
[0002] Currently, the on-load tap changers used in 35kV and above transformers in the power grid market mainly include oil-immersed mechanical on-load tap changers and oil-immersed vacuum on-load tap changers. Oil-immersed mechanical on-load tap changers have a large contact opening distance, reliable arc extinguishing, and a mature mechanical design, exhibiting excellent reliability and safety. However, the mechanical contacts of this type of switch arc in the oil and are extinguished in the oil, resulting in severe contact burn-out, high levels of oil carbonization and contamination, and high maintenance costs.
[0003] Oil-immersed vacuum on-load tap changers generate an electric arc in the vacuum tube, which is extinguished by the vacuum, thus solving the problems of oil carbonization and contamination. However, this type of switch cannot completely prevent the generation of an electric arc; the empty tube contacts will burn out, and safety depends on the vacuum level. Once the vacuum level drops, an accident will occur. Both of these types of switches are arc switches, and the electric arc causes energy loss. This energy will cause the oil temperature to rise, and the burnt contacts will reduce the electrical life of the switch.
[0004] Therefore, how to achieve arc-free switching of on-load tap changers is a technical problem that urgently needs to be solved in this field. Utility Model Content
[0005] To solve the above-mentioned technical problems, this utility model proposes the following technical solution:
[0006] This utility model embodiment provides a thyristor-mechanical hybrid switching circuit, including: a thyristor module disposed between a first tap and a second tap of a transformer, multiple vacuum tube pairs, auxiliary contacts electrically connected to the vacuum tube pairs, and trigger contacts corresponding to the auxiliary contacts. The first end of the thyristor module is electrically connected to the auxiliary contacts, the trigger electrode of the thyristor module is electrically connected to the first end of the trigger contacts, the second end of the trigger contacts is electrically connected to the middle end of the corresponding vacuum tube pairs, and the second end of the thyristor module is electrically connected to the current output terminal.
[0007] In one possible implementation, the vacuum tube pair includes: a first vacuum tube pair, a second vacuum tube pair, a third vacuum tube pair, and a fourth vacuum tube pair.
[0008] In one possible implementation, the first end of the first vacuum tube pair is electrically connected to the first tap, the first end of the first side current-limiting resistor, and the first end of the first auxiliary contact, respectively. The second end of the first side current-limiting resistor is electrically connected to the first end of the second auxiliary contact and the first end of the second vacuum tube pair, respectively. The second ends of the first auxiliary contact and the second auxiliary contact are electrically connected to the first end of the thyristor module. The second ends of the first vacuum tube pair, the second vacuum tube pair, and the second end of the thyristor module are all electrically connected to the current output terminal.
[0009] In one possible implementation, the first end of the third vacuum tube pair is electrically connected to the first end of the second tap, the first end of the second side current-limiting resistor, and the first end of the third auxiliary tap, respectively. The second end of the second side current-limiting resistor is electrically connected to the first end of the fourth vacuum tube pair and the first end of the fourth auxiliary contact, respectively. The second ends of the third auxiliary contact and the fourth auxiliary contact are both electrically connected to the first end of the thyristor module. The second ends of the third vacuum tube pair and the fourth vacuum tube pair are both electrically connected to the current output terminal.
[0010] In one possible implementation, the trigger contact is provided with the same number of auxiliary contacts, including: a first trigger contact, a second trigger contact, a third trigger contact, and a fourth trigger contact.
[0011] In one possible implementation, the trigger electrode of the thyristor module is electrically connected to the first end of the first trigger contact, the first end of the second trigger contact, the first end of the third trigger contact, and the first end of the fourth trigger contact, respectively. The second end of the first trigger contact is electrically connected to the middle end of the first vacuum tube pair, the second end of the second trigger contact is electrically connected to the middle end of the second vacuum tube pair, the second end of the third trigger contact is electrically connected to the middle end of the third vacuum tube pair, and the second end of the fourth trigger contact is electrically connected to the middle end of the fourth vacuum tube pair.
[0012] In one possible implementation, the thyristor module includes a first thyristor, the gate of which is electrically connected to the negative terminal of a first diode, the positive terminal of which is electrically connected to a first end of a first resistor, the second end of which is electrically connected to a first end of a second resistor and a trigger electrode, the second end of which is electrically connected to the positive terminal of a second diode, the negative terminal of which is electrically connected to the gate of a second thyristor, the anode of which is electrically connected to a first end of a varistor and a cathode of a second thyristor, and the anode of which is electrically connected to the cathode of the first thyristor and a second end of the varistor.
[0013] In one possible implementation, the vacuum tube pair has a double-break structure, and the auxiliary contact and the trigger contact have a single-break structure.
[0014] Compared with the prior art, the beneficial effects of this utility model are as follows:
[0015] In this invention, a single pair of thyristors is triggered by a mechanically connected series break voltage, avoiding the generation of mechanical break arcs and achieving arc-free switching, which significantly improves the electrical life of the on-load tap changer. Attached Figure Description
[0016] Figure 1 A schematic diagram of a thyristor-mechanical hybrid switching circuit provided for an embodiment of this utility model;
[0017] Figure 2 A schematic diagram of the circuit structure of the thyristor module provided in this embodiment of the utility model. Detailed Implementation
[0018] The present solution will now be described in conjunction with the accompanying drawings and specific embodiments.
[0019] Figure 1 A schematic diagram of a thyristor-mechanical hybrid switching circuit provided in an embodiment of this application is shown below. Figure 1 This embodiment of a thyristor-mechanical hybrid switching circuit includes: a thyristor module VT disposed between a first tap n and a second tap n+1 of a transformer, multiple vacuum tube pairs, auxiliary contacts electrically connected to the vacuum tube pairs, and trigger contacts corresponding to the auxiliary contacts. The first end of the thyristor module is electrically connected to the auxiliary contacts, the trigger electrode of the thyristor module is electrically connected to the first end of the trigger contacts, the second end of the trigger contacts is electrically connected to the middle end of the corresponding vacuum tube pairs, and the second end of the thyristor module is electrically connected to the current output terminal.
[0020] In this embodiment, the vacuum tube pairs include: a first vacuum tube pair VA1, VA2, a second vacuum tube pair VB1, VB2, a third vacuum tube pair VD1, VD2, and a fourth vacuum tube pair VC1, VC2. Each vacuum tube pair is connected in series, and the connection point between them is called the middle end of the vacuum tube pair. The trigger contact is provided with the same number of auxiliary contacts as the auxiliary contact, including: a first trigger contact A", a second trigger contact B", a third trigger contact D", and a fourth trigger contact C". In this embodiment, the vacuum tube has a double-break structure, and the auxiliary contact and the trigger contact have a single-break structure. Specifically, the first end VA1 of the first vacuum tube pair is electrically connected to the first tap n, the first end of the first side current limiting resistor R1, and the first end of the first auxiliary contact A', respectively. The second end of the first side current limiting resistor R1 is electrically connected to the first end of the second auxiliary contact B' and the first end VB1 of the second vacuum tube pair, respectively. The second end of the first auxiliary contact A' and the second end of the second auxiliary contact B' are electrically connected to the first end of the thyristor module VT. The second end VA2 of the first vacuum tube pair, the second end VB2 of the second vacuum tube pair, and the second end of the thyristor module VT are all electrically connected to the current output terminal O.
[0021] The first end VD1 of the third vacuum tube pair is electrically connected to the first end of the second tap n+1, the first end of the second side current limiting resistor R2, and the first end of the third auxiliary tap D'. The second end of the second side current limiting resistor R2 is electrically connected to the first end VC1 of the fourth vacuum tube pair and the first end of the fourth auxiliary contact C'. The second ends of the third auxiliary contact D' and the fourth auxiliary contact C' are both electrically connected to the first end of the thyristor module VT. The second ends VD2 of the third vacuum tube pair and VC2 of the fourth vacuum tube pair are both electrically connected to the current output terminal O.
[0022] The trigger electrode of the thyristor module is electrically connected to the first end of the first trigger contact A", the first end of the second trigger contact B", the first end of the third trigger contact D", and the first end of the fourth trigger contact C". The second end of the first trigger contact A" is electrically connected to the middle end of the first vacuum tube pair, the second end of the second trigger contact B" is electrically connected to the middle end of the second vacuum tube pair, the second end of the third trigger contact D" is electrically connected to the middle end of the third vacuum tube pair, and the second end of the fourth trigger contact C" is electrically connected to the middle end of the fourth vacuum tube pair.
[0023] See Figure 2 In this embodiment, two thyristors are connected in antiparallel to form a first terminal and a second terminal, respectively.
[0024] The thyristor module includes a first thyristor SCR1. The gate of the first thyristor is electrically connected to the negative terminal of a first diode D1. The positive terminal of the first diode D1 is electrically connected to the first end of a first resistor r1. The second end of the first resistor r1 is electrically connected to the first end of a second resistor r2 and the trigger electrode C. The second end of the second resistor r2 is electrically connected to the positive terminal of a second diode D2. The negative terminal of the second diode D2 is electrically connected to the gate of the second thyristor SCR2. The anode of the first thyristor SCR1 is electrically connected to the first end of a varistor R and the cathode of the second thyristor SCR2. The anode of the second thyristor SCR2 is electrically connected to the cathode of the first thyristor SCR1 and the second end of the varistor R. In this embodiment, the varistor is used to protect the thyristor module from overvoltage damage, the diode is used to prevent gate reverse current, and the resistor is used to limit the gate current.
[0025] In this embodiment, the thyristor module triggering process is as follows: AC current flows from the first tap n to the current output terminal O. At the instant the first vacuum tube opens VA1 and VA2, the first vacuum tube generates a break voltage at the two breaks at the left and right ends of VA1 and VA2. The break voltage at VA1 forms a positive bias voltage for the upper thyristor SCR of VT, and the break voltage at VA2 forms a trigger voltage for the upper thyristor SCR of VT, generating a trigger current. The upper thyristor of VT is turned on, and the current flows from n—A'—the first end of VT—the upper thyristor SCR1 of VT—the second end of VT—the current output terminal O.
[0026] In this embodiment, the switching process of the thyristor-mechanical hybrid switching circuit from the first tap n of the transformer to the second tap n+1 is as follows:
[0027] When the first vacuum tube pairs VA1 and VA2 are closed, the first auxiliary contact A' and the first trigger contact A" are closed; the second vacuum tube pairs VB1 and VB2 are closed; the second auxiliary contact B' and the second trigger contact B" are open; the fourth vacuum tube pairs VC1 and VC2 are open; the fourth auxiliary contact C' and the fourth trigger contact C" are open; the third vacuum tube pairs VD1 and VD2 are open; and the third auxiliary contact D' and the third trigger contact D" are open, the current flows from the first tap n—the first vacuum tube pairs VA1 and VA2—to the current output terminal O.
[0028] When the first vacuum tube pairs VA1 and VA2 are opened, the first auxiliary contact A' and the first trigger contact A" are closed; the second vacuum tube pairs VB1 and VB2 are closed; the second auxiliary contact B' and the second trigger contact B" are open; the fourth vacuum tube pairs VC1 and VC2 are open; the fourth auxiliary contact C' and the fourth trigger contact C" are open; the third vacuum tube pairs VD1 and VD2 are open; the third auxiliary contact D' and the third trigger contact D" are open. At the instant the first vacuum tube pairs VA1 and VA2 are opened, a break voltage is generated on both the left and right breaks. This break voltage is applied to the thyristor module VT, triggering the thyristor to conduct. Current flows from the first tap n - the first auxiliary contact A' - VT to the current output terminal O. After the thyristor module VT naturally turns off when the current crosses zero, the current flows from the first tap n - the first resistor R1 - the second vacuum tube pairs VB1 and VB2 into the current output terminal O.
[0029] When the first vacuum tube pairs VA1 and VA2 are open, the first auxiliary contact A' and the first trigger contact A" are open, the second vacuum tube pairs VB1 and VB2 are closed, the second auxiliary contact B' and the second trigger contact B" are open, the fourth vacuum tube pairs VC1 and VC2 are open; the fourth auxiliary contact C' and the fourth trigger contact C" are open; the third vacuum tube pairs VD1 and VD2 are open; the third auxiliary contact D' and the third trigger contact D" are open, and the current flows from the first tap n—the first resistor R1—the second vacuum tube pairs VB1 and VB2 into the current output terminal O.
[0030] When the first vacuum tube pairs VA1 and VA2 are open, the first auxiliary contact A' and the first trigger contact A" are open, the second vacuum tube pairs VB1 and VB2 are closed, the second auxiliary contact B' and the second trigger contact B" are open, and the fourth vacuum tube pairs VC1 and VC2 are open; the fourth auxiliary contact C' and the fourth trigger contact C" are closed; the third vacuum tube pairs VD1 and VD2 are open; and the third auxiliary contact D' and the third trigger contact D" are open, the current flows from the first tap n—the first resistor R1—the second vacuum tube pairs VB1 and VB2 into the current output terminal O.
[0031] When the first vacuum tube is open to VA1 and VA2, the first auxiliary contact A' and the first trigger contact A" are open; the second vacuum tube is closed to VB1 and VB2; the second auxiliary contact B' and the second trigger contact B" are open; the fourth vacuum tube is closed to VC1 and VC2; the fourth auxiliary contact C' and the fourth trigger contact C" are closed; when the third vacuum tube is open to VD1 and VD2; the third auxiliary contact D' and the third trigger contact D" are open, at the instant the fourth vacuum tube closes and bounces to VC1 and VC2, the current flows from the first tap n. —The first resistor R1—The second vacuum tube pairs VB1 and VB2 flow into the current output terminal O, and at the same time, the current flows from the second tap n+1—the second resistor R2—the fourth auxiliary contact C'—VT—the current output terminal O; When the fourth vacuum tube pairs VC1 and VC2 are fully closed, the current flows from the first tap n—the first resistor R1—the second vacuum tube pairs VB1 and VB2 into the current output terminal O, and at the same time, the current flows from the second tap n+1—the second resistor R2—the fourth vacuum tube pairs VC1 and VC2 into the current output terminal O, forming a bridge between n and n+1.
[0032] When the first vacuum tube pairs VA1 and VA2 are open, the first auxiliary contact A' and the first trigger contact A" are open, the second vacuum tube pairs VB1 and VB2 are closed, the second auxiliary contact B' and the second trigger contact B" are closed, and the fourth vacuum tube pairs VC1 and VC2 are closed; the fourth auxiliary contact C' and the fourth trigger contact C" are open; when the third vacuum tube pairs VD1 and VD2 are open; and the third auxiliary contact D' and the third trigger contact D" are open, the current flows from the first tap n—the first resistor R1—the second vacuum tube pairs VB1 and VB2 into the current output terminal O, and at the same time, the current flows from the second tap n+1—the second resistor R2—the fourth vacuum tube pairs VC1 and VC2 into the current output terminal O, forming a continued bridging between n and n+1.
[0033] When the first vacuum tube pairs VA1 and VA2 are open, the first auxiliary contact A' and the first trigger contact A" are open; the second vacuum tube pairs VB1 and VB2 are open; the second auxiliary contact B' and the second trigger contact B" are closed; and the fourth vacuum tube pairs VC1 and VC2 are closed. The fourth auxiliary contact C' and the fourth trigger contact C" are open. When the third vacuum tube pairs VD1 and VD2 are open, and the third auxiliary contact D' and the third trigger contact D" are open, a break voltage is generated on both the left and right breaks at the instant the second vacuum tube pairs VB1 and VB2 are opened. This break voltage is applied to the thyristor module VT, triggering the thyristor to conduct. The original current from the second vacuum tube pairs VB1 and VB2 flows through the thyristor module VT to the current output terminal O. The thyristor module VT naturally turns off when the current crosses zero. The current flows from the second tap n+1—the second resistor R2—to the fourth vacuum tube pairs VC1 and VC2 into the current output terminal O, with the bridge between n and n+1 disconnected.
[0034] When the first vacuum tube pairs VA1 and VA2 are open, the first auxiliary contact A' and the first trigger contact A" are open; the second vacuum tube pairs VB1 and VB2 are open; the second auxiliary contact B' and the second trigger contact B" are open; and the fourth vacuum tube pairs VC1 and VC2 are closed. The fourth auxiliary contact C' and the fourth trigger contact C" are open. When the third vacuum tube pairs VD1 and VD2 are open, and the third auxiliary contact D' and the third trigger contact D" are closed, the current flows from the second tap n+1—the second resistor R2—the fourth vacuum tube pairs VC1 and VC2 into the current output terminal O.
[0035] When the first vacuum tube pairs VA1 and VA2 are open, the first auxiliary contact A' and the first trigger contact A" are open; the second vacuum tube pairs VB1 and VB2 are open; the second auxiliary contact B' and the second trigger contact B" are open; the fourth vacuum tube pairs VC1 and VC2 are closed; the fourth auxiliary contact C' and the fourth trigger contact C" are open; the third vacuum tube pairs VD1 and VD2 are closed; when the third auxiliary contact D' and the third trigger contact D" are closed, if there is a bounce during the closing process of the third vacuum tube pairs VD1 and VD2, the thyristor VT is triggered to conduct momentarily. Then, as the closing of the third vacuum tube pairs VD1 and VD2 is completed, VT is quickly short-circuited by the third vacuum tube pairs VD1 and VD2. Current flows from the second tap n+1 to the third vacuum tube pairs VD1 and VD2 into the current output terminal O.
[0036] The above process uses a single thyristor dual-resistor circuit to achieve the conversion of transformer tap n to n+1. If the conversion is to transformer tap n+1 to n, the reverse process can be used.
[0037] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.
[0038] The above description is merely a specific embodiment of this utility model. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this utility model should be included within the protection scope of this utility model. The protection scope of this utility model should be determined by the scope of the claims.
Claims
1. A mechanical hybrid switching circuit for a thyristor, characterized by The application relates to a transformer with a thyristor module, a plurality of vacuum tube pairs and a plurality of auxiliary contacts and trigger contacts corresponding to the auxiliary contacts. The vacuum tube pairs comprise a first vacuum tube pair, a second vacuum tube pair, a third vacuum tube pair and a fourth vacuum tube pair.
2. The thyristor mechanical hybrid switching circuit according to claim 1, characterized in that, The first end of the first vacuum tube pair is electrically connected with the first tapping, the first end of the first side current-limiting resistor and the first end of the first auxiliary contact, the second end of the first side current-limiting resistor is electrically connected with the first end of the second auxiliary contact and the first end of the second vacuum tube pair, the second end of the first auxiliary contact and the second end of the second auxiliary contact are electrically connected with the first end of the thyristor module, and the second end of the first vacuum tube pair, the second end of the second vacuum tube pair and the second end of the thyristor module are electrically connected with the current output end.
3. The thyristor mechanical hybrid switching circuit according to claim 2, characterized in that, The first end of the third vacuum tube pair is electrically connected with the second tapping, the first end of the second side current-limiting resistor and the first end of the third auxiliary contact, the second end of the second side current-limiting resistor is electrically connected with the first end of the fourth vacuum tube pair and the first end of the fourth auxiliary contact, the second end of the third auxiliary contact and the second end of the fourth auxiliary contact are electrically connected with the first end of the thyristor module, and the second end of the third vacuum tube pair and the second end of the fourth vacuum tube pair are electrically connected with the current output end.
4. The thyristor mechanical hybrid switching circuit according to claim 3, characterized in that, The trigger contacts correspond to the auxiliary contacts in the same number, and the trigger contacts comprise a first trigger contact, a second trigger contact, a third trigger contact and a fourth trigger contact.
5. A thyristor mechanical hybrid switching circuit according to claim 4, characterized in that, The trigger poles of the thyristor module are electrically connected with the first end of the first trigger contact, the first end of the second trigger contact, the first end of the third trigger contact and the first end of the fourth trigger contact, the second end of the first trigger contact is electrically connected with the middle end of the first vacuum tube pair, the second end of the second trigger contact is electrically connected with the middle end of the second vacuum tube pair, the second end of the third trigger contact is electrically connected with the middle end of the third vacuum tube pair, and the second end of the fourth trigger contact is electrically connected with the middle end of the fourth vacuum tube pair.
6. The thyristor mechanical hybrid switch circuit according to claim 5, characterized in that, The thyristor module comprises a first thyristor, the gate of the first thyristor is electrically connected with the negative pole of a first diode, the positive pole of the first diode is electrically connected with the first end of a first resistor, the second end of the first resistor is electrically connected with the first end of a second resistor and a trigger pole, the second end of the second resistor is electrically connected with the positive pole of a second diode, the negative pole of the second diode is electrically connected with the gate of a second thyristor, the anode of the first thyristor is electrically connected with the first end of a voltage-dependent resistor and the cathode of the second thyristor, and the anode of the second thyristor is electrically connected with the cathode of the first thyristor and the second end of the voltage-dependent resistor.
7. The thyristor mechanical hybrid switching circuit according to claim 1, characterized in that, 8. The thyristor mechanical hybrid switching circuit of claim 1, wherein, The vacuum tube pair is a double-break structure, and the auxiliary contact and the trigger contact are single-break structures.