A distribution transformer based on low-voltage side voltage regulation

Abstract

The utility model discloses a kind of distribution transformer based on low-voltage side voltage regulation, including transformer body and the adjusting device of being set in transformer body low-voltage side, wherein, the low-voltage side coil of transformer body includes fixed coil and the access coil in series with fixed coil;N taps are equipped on the access coil, form N nodes;The adjusting device includes N identical voltage regulation module, and the input end of each voltage regulation module is respectively connected with the corresponding node of access coil, and N voltage regulation module is common first voltage output end;Two ends of access coil are respectively connected to one end of fixed coil by a coil throw-off thyristor, and the other end of fixed coil is second voltage output end.The utility model structure is simple, can realize distribution transformer low-voltage side voltage regulation, to avoid high-voltage insulation problem, realize quick, flexible, low-cost voltage regulation.

Description

Technical Field

[0001] This utility model relates to the field of power distribution network voltage regulation technology, specifically to a power distribution transformer based on low-voltage side voltage regulation. Background Technology

[0002] Currently, in 10kV and 35kV distribution networks, distribution transformers typically employ on-load automatic voltage regulation (OTCR) to control the voltage on the low-voltage side of the grid, ensuring voltage quality at the power supply terminals. Traditional OCR systems are generally located on the high-voltage side and use mechanical on-load switches for voltage regulation. The design of these switches must consider the insulation distance on the high-voltage side, resulting in large size and bulky structure. If power electronic devices are used for voltage regulation on the high-voltage side, the limited voltage withstand capability of these devices necessitates multiple devices connected in series to improve their withstand capacity. This not only reduces system reliability but also increases the size and cost of the voltage regulation device due to the high-voltage insulation requirements.

[0003] With the integration of highly volatile loads such as new energy sources and electric vehicles, the voltage of the distribution network is experiencing wide and rapid fluctuations. Traditional high-voltage side voltage regulation methods are insufficient to meet the demands for rapid and wide-range voltage regulation. Therefore, there is an urgent need for a low-voltage side voltage regulation solution that is simple in structure, fast in adjustment, and low in cost. Utility Model Content

[0004] The technical problem to be solved by this utility model is to provide a distribution transformer based on low-voltage side voltage regulation, which can realize low-voltage side voltage regulation of the distribution transformer, thereby avoiding high-voltage insulation problems and achieving fast, flexible and low-cost voltage regulation.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by this utility model is as follows.

[0006] A distribution transformer based on low-voltage side voltage regulation includes a transformer body and a regulating device disposed on the low-voltage side of the transformer body. The low-voltage side coil of the transformer body includes a fixed coil and an access coil connected in series with the fixed coil. The access coil has N taps, forming N nodes. The regulating device includes N identical voltage regulating modules. The input terminal of each voltage regulating module is connected to a corresponding node of the access coil, and the N voltage regulating modules share a first voltage output terminal. The two ends of the access coil are respectively connected to one end of the fixed coil through a coil switching thyristor, and the other end of the fixed coil is a second voltage output terminal.

[0007] Preferably, the voltage regulating module includes a current-limiting resistor, a resistor-on / off thyristor for controlling the current-limiting resistor's engagement and disengagement, and a main thyristor for short-circuiting the current-limiting resistor; the input terminal of the current-limiting resistor is connected to a corresponding node of the input coil, the resistor-on / off thyristor is connected in series with the current-limiting resistor, and the main thyristor is connected in parallel with the series branch of the current-limiting resistor and the resistor-on / off thyristor.

[0008] Preferably, the current-limiting resistor is a power resistor.

[0009] Preferably, the coil engagement / disengagement thyristor includes a forward thyristor for the access coil and a reverse thyristor for the access coil; the forward thyristor for the access coil is connected between the beginning of the access coil and the fixed coil, and the reverse thyristor for the access coil is connected between the end of the access coil and the fixed coil. The coil engagement / disengagement thyristor is used to control the direction of the access coil's connection to the circuit.

[0010] The technological advancements achieved by this utility model are as follows, due to the adoption of the above technical solutions.

[0011] This utility model has a simplified structure and reduced cost: the voltage regulating device is entirely located on the low-voltage side, eliminating the need to consider high-voltage insulation issues; the device is small in size, compact in structure, and low in manufacturing cost.

[0012] This invention offers rapid and flexible voltage adjustment: it achieves arc-free voltage switching through the rapid switching of thyristors, and combines this with the forward and reverse thyristor control of the coil direction to expand the voltage regulation range and number of stages.

[0013] This invention boasts high reliability: all power electronic devices operate in a low-voltage environment and do not require series connection, thus avoiding device damage caused by voltage equalization issues.

[0014] This utility model has strong applicability: it is applicable to low-voltage side voltage regulation of various distribution transformers, and is particularly suitable for dealing with voltage fluctuation problems caused by the access of new energy and electric vehicles. Attached Figure Description

[0015] Figure 1 This is the circuit diagram of this utility model.

[0016] Wherein: BYQ. Transformer body, JRXQ. Connecting coil, GDXQ. Fixed coil, TJZZ. Adjusting device, Kf. Reverse thyristor of connecting coil, KZ. Forward thyristor of connecting coil, R1. Current limiting resistor of the first voltage regulating module, K1R. Thyristor for switching on / off of the first voltage regulating module, K1. Main thyristor of the first voltage regulating module, R2. Current limiting resistor of the second voltage regulating module, K2R. Thyristor for switching on / off of the second voltage regulating module, K2. Main thyristor of the second voltage regulating module, RN. Current limiting resistor of the Nth voltage regulating module, KNR. Thyristor for switching on / off of the Nth voltage regulating module, KN. Main thyristor of the Nth voltage regulating module. Detailed Implementation

[0017] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0018] A distribution transformer based on low-voltage side voltage regulation, combined with Figure 1 As shown, the device includes a transformer body BYQ and a regulating device TJZZ. The low-voltage side coil of the transformer body BYQ includes a fixed coil GDXQ and an access coil JRXQ, which are connected in series. The access coil JRXQ has N taps, forming N nodes, where N is an integer greater than or equal to 2. The regulating device TJZZ includes N identical voltage regulating modules. The input terminal of each voltage regulating module is connected to a corresponding node of the access coil JRXQ, and the N voltage regulating modules share a common first voltage output terminal. Simultaneously, both ends of the access coil are connected to one end of the fixed coil via a coil-on / off thyristor, and the other end of the fixed coil is the second voltage output terminal.

[0019] Each voltage regulating module includes a current-limiting resistor, a resistor-on / off thyristor, and a main thyristor. The input terminal of the current-limiting resistor is connected to a corresponding node of the input coil. The current-limiting resistor is a power resistor with high power tolerance, excellent thermal stability, structural reliability, and safety, ensuring long-term stable operation of the voltage regulating device TJZZ under frequent switching conditions. The resistor-on / off thyristor is connected in series with the current-limiting resistor and is used to control the activation and deactivation of the current-limiting resistor. The main thyristor is connected in parallel with the series branch of the current-limiting resistor and the resistor-on / off thyristor and is used to short-circuit the current-limiting resistor.

[0020] Taking the first voltage regulating module as an example, the input terminal of the current-limiting resistor R1 of the first voltage regulating module is connected to the first node of the coil JRXQ; the resistor-on / off thyristor K1R of the first voltage regulating module is connected in series with the current-limiting resistor R1 of the first voltage regulating module; the main thyristor K1 of the first voltage regulating module is connected in parallel in the series branch of the current-limiting resistor R1 and the resistor-on / off thyristor K1R of the first voltage regulating module. The structures of the remaining voltage regulating modules are the same. For example, the second voltage regulating module includes the current-limiting resistor R2 of the second voltage regulating module, the resistor-on / off thyristor K2R of the second voltage regulating module, and the main thyristor K2 of the second voltage regulating module; the Nth voltage regulating module includes the current-limiting resistor RN of the Nth voltage regulating module, the resistor-on / off thyristor KNR of the Nth voltage regulating module, and the main thyristor KN of the Nth voltage regulating module.

[0021] The coil-connecting thyristor is used to control the direction of the access coil to the circuit. It includes a forward thyristor KZ and a reverse thyristor Kf. The forward thyristor is connected between the beginning of the access coil and the fixed coil, and the reverse thyristor is connected between the end of the access coil and the fixed coil.

[0022] In use, this invention regulates the output voltage by controlling the on / off state of each thyristor in the regulating device TJZZ, thereby changing the connection method and number of turns of the input coil JRXQ. The specific working principle is as follows: Voltage regulation process: When voltage needs to be adjusted, the switching sequence of the resistor and the main thyristor in the corresponding voltage regulation module is controlled. First, the current limiting resistor is engaged to limit the switching current, and then the current limiting resistor is shorted to complete the gear switching, thus achieving arc-free and smooth voltage regulation. Direction control: By controlling the on / off state of the forward thyristor KZ and the reverse thyristor Kf of the input coil, the input direction of the input coil JRXQ is changed, thereby increasing or decreasing the voltage and expanding the number of voltage regulation stages. Low-voltage advantages: All thyristors and current-limiting resistors operate on the low-voltage side, eliminating the need for multiple devices connected in series to increase withstand voltage as is required on the high-voltage side. There is also no need to consider the insulation requirements of the high-voltage side voltage level. The structure is compact, the cost is low, and the reliability is high.

[0023] The working principle of this utility model is illustrated below with specific operational examples: (1) Example of voltage adjustment operation: For example, if the forward thyristor Kz of the input coil is engaged, and the current gear is at level 2 (i.e., the second voltage regulation module is engaged), and the output voltage of 0.4kV is too low and needs to be increased, firstly, the first voltage regulation module resistor is switched on / off, and the thyristor K1R is closed. Then, the main thyristor K2 of the second voltage regulation module is disconnected, and then the main thyristor K1 of the first voltage regulation module is closed. Finally, the first voltage regulation module resistor is disconnected, and the thyristor K1R is switched on / off, thus increasing the output voltage from 0.4kV.

[0024] If the output voltage of 0.4kV is too high and needs to be reduced, first close the thyristor K3R of the third voltage regulating module resistor, then open the main thyristor K2 of the second voltage regulating module, then close the main thyristor K3 of the third voltage regulating module, and then open the third voltage regulating module resistor to reduce the output voltage by 0.4kV.

[0025] (2) Example of voltage adjustment operation: For example, if the forward thyristor Kz of the access coil is engaged, and the current gear is in the N gear, and the current output voltage of 0.4kV is still too high, requiring a voltage reduction, firstly, engage the thyristor K1R of the first voltage regulating module and engage the reverse thyristor Kf of the access coil; then, deengage the main thyristor KN of the Nth voltage regulating module and the forward thyristor KZ of the access coil; finally, engage the main thyristor K1 of the first voltage regulating module to complete the forward and reverse adjustment of the access coil JRXQ.

[0026] Next, the second voltage regulating module resistor is switched on and off, thyristor K2R is switched on, the first voltage regulating module main thyristor K1 is switched off, the second voltage regulating module main thyristor K2 is switched on, and then the second voltage regulating module resistor is switched on and off, thyristor K2R is switched off, thus completing the reduction of the output voltage by 0.4kV.

[0027] Other operation examples are similar to those in the examples above.

[0028] This utility model has a simple structure and flexible operation, and is suitable for low-voltage side voltage regulation scenarios of various distribution transformers, with high practical value and economic benefits.

Claims

1. A distribution transformer based on low-voltage side voltage regulation, comprising a transformer body and a regulating device disposed on the low-voltage side of the transformer body, characterized in that: The low-voltage side coil of the transformer body includes a fixed coil and an access coil connected in series with the fixed coil; the access coil has N taps, forming N nodes; the regulating device includes N identical voltage regulating modules, the input terminal of each voltage regulating module is connected to a corresponding node of the access coil, and the N voltage regulating modules share a first voltage output terminal; the two ends of the access coil are respectively connected to one end of the fixed coil through a coil switching thyristor, and the other end of the fixed coil is the second voltage output terminal.

2. A distribution transformer based on low-voltage side voltage regulation according to claim 1, characterized in that: The voltage regulation module includes a current-limiting resistor, a resistor-on / off thyristor for controlling the current-limiting resistor's engagement and disengagement, and a main thyristor for short-circuiting the current-limiting resistor. The input terminal of the current-limiting resistor is connected to a corresponding node of the input coil. The resistor-on / off thyristor is connected in series with the current-limiting resistor, and the main thyristor is connected in parallel with the series branch of the current-limiting resistor and the resistor-on / off thyristor.

3. A distribution transformer based on low-voltage side voltage regulation according to claim 2, characterized in that: The current-limiting resistor is a power resistor.

4. A distribution transformer based on low-voltage side voltage regulation according to claim 1, characterized in that: The coil engagement / disengagement thyristor includes a forward thyristor for the access coil and a reverse thyristor for the access coil; the forward thyristor for the access coil is connected between the beginning of the access coil and the fixed coil, and the reverse thyristor for the access coil is connected between the end of the access coil and the fixed coil. The coil engagement / disengagement thyristor is used to control the direction of the access coil's connection to the circuit.

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