CN111884551A - Synchronous generator de-excitation circuit based on thermistor - Google Patents
Synchronous generator de-excitation circuit based on thermistor Download PDFInfo
- Publication number
- CN111884551A CN111884551A CN202010794347.3A CN202010794347A CN111884551A CN 111884551 A CN111884551 A CN 111884551A CN 202010794347 A CN202010794347 A CN 202010794347A CN 111884551 A CN111884551 A CN 111884551A
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- China
- Prior art keywords
- synchronous generator
- thermistor
- circuit
- field suppression
- resistor
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Classifications
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- H02P9/00—Arrangements for controlling electric generators for the purpose of obtaining a desired output
- H02P9/10—Control effected upon generator excitation circuit to reduce harmful effects of overloads or transients, e.g. sudden application of load, sudden removal of load, sudden change of load
- H02P9/12—Control effected upon generator excitation circuit to reduce harmful effects of overloads or transients, e.g. sudden application of load, sudden removal of load, sudden change of load for demagnetising; for reducing effects of remanence; for preventing pole reversal
- H02P9/123—Control effected upon generator excitation circuit to reduce harmful effects of overloads or transients, e.g. sudden application of load, sudden removal of load, sudden change of load for demagnetising; for reducing effects of remanence; for preventing pole reversal for demagnetising; for reducing effects of remanence
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
- H02H7/06—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for dynamo-electric generators; for synchronous capacitors
- H02H7/062—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for dynamo-electric generators; for synchronous capacitors for parallel connected generators
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
- H02H7/06—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for dynamo-electric generators; for synchronous capacitors
- H02H7/065—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for dynamo-electric generators; for synchronous capacitors against excitation faults
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- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Control Of Eletrric Generators (AREA)
Abstract
A synchronous generator field suppression circuit based on thermistors comprises a generator rectifying circuit, a magnetic field breaker and a synchronous generator field winding, wherein the synchronous generator field winding is also connected with a field suppression circuit in parallel, the field suppression circuit comprises thermistors and nonlinear field suppression resistors, and the thermistors and the nonlinear field suppression resistors are connected in series.
Description
Technical Field
The invention relates to the technical field of synchronous generator rotor loop field of demagnetization, in particular to a synchronous generator demagnetization circuit based on a thermistor.
Background
The excitation system is an important component of the synchronous generator, not only directly influences the operating characteristics of the synchronous generator, but also plays an important role in the stability of the power system. The field suppression is the most critical and most complex part of theory and technology in the excitation system.
In a traditional method for demagnetizing a synchronous generator, two devices, namely a power electronic device (also called an electronic switch) and a breaker (or a load switch) are usually selected as a closed switch device of a main circuit for demagnetizing, so that the conventional demagnetizing device of the synchronous generator generally has the problems of high manufacturing cost, complex control circuit, low reliability and the like. The reliability problem can cause that the safe and stable operation of the synchronous generator is finally directly endangered due to the lack of the field suppression function when the field suppression of the synchronous generator excitation system is carried out.
Disclosure of Invention
Technical problem to be solved
The invention aims to provide a thermistor-based synchronous generator de-excitation circuit to solve the practical problems in the background technology.
(II) technical scheme
In order to achieve the purpose, the invention provides the following technical scheme: the utility model provides a synchronous generator deexcitation circuit based on thermistor, includes generator rectifier circuit, magnetic field circuit breaker and synchronous generator excitation winding, synchronous generator excitation winding still has deexcitation circuit in parallel, the deexcitation circuit includes thermistor and non-linear deexcitation resistance just thermistor with non-linear deexcitation resistance series connection.
Preferably, the nonlinear demagnetization resistor is a zinc oxide (ZnO) demagnetization resistor.
Preferably, the nonlinear field suppression resistor is a silicon carbide (SiC) field suppression resistor.
Preferably, the demagnetization circuit further comprises a rotor overvoltage protection circuit, the rotor overvoltage protection circuit comprises a thyristor, the thyristor is connected with the thermistor in parallel, one end of the thyristor is connected with an overvoltage trigger, and the overvoltage trigger is connected with two ends of the excitation winding of the synchronous generator.
(III) advantageous effects
The invention selects the thermistor (PTC) with positive temperature characteristic as the closed switch of the main de-excitation loop, solves the problems of higher manufacturing cost of the de-excitation device, complex control loop, lower reliability and the like of the de-excitation method of the traditional synchronous generator, is one of important guarantee measures for the safe and stable operation of the synchronous generator, and has important practical significance for power generation engineering in China.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained according to the drawings without creative efforts.
FIG. 1 is a schematic view of the overall structure of the present invention;
fig. 2 is a schematic structural diagram of embodiment 2 of the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Referring to fig. 1, the present invention provides a technical solution: the embodiment 1 of the invention discloses a thermistor-based synchronous generator field suppression circuit, which comprises a generator rectifying circuit, a magnetic field breaker and a synchronous generator excitation winding, wherein the synchronous generator excitation winding is also connected with a field suppression circuit in parallel, and the field suppression circuit comprises a thermistor and a nonlinear field suppression resistor which are connected in series.
The working principle is as follows: after the magnetic field circuit breaker receives the breaking signal, the main contacts start to separate and generate arc voltage UFMKAt this time, the output voltage U of the rectifying circuitZAnd arc voltage UFMKUnder the combined action, the exciting current I of the synchronous generatorfTransferring from the rotor loop (see the dotted arrow in fig. 1) to the de-excitation main loop (see the solid arrow in fig. 1), de-excitation of the synchronous generator is started, and the excitation current I isfThe electromagnetic energy stored in the excitation winding before the demagnetization starts is gradually converted into the heat energy of the demagnetization resistor. In this process, a thermistor: (PTC) also starts to heat, the temperature gradually rises, the resistance value also increases due to the positive temperature characteristic, when the temperature rises to a certain set range, the resistance value suddenly increases or sharply increases, correspondingly, the passing current also suddenly decreases, at this moment, the thermistor is equivalently in a disconnected state, finally, the consumption of electromagnetic energy in the excitation winding is realized, and the demagnetization of the synchronous generator is finished.
The specific temperature range requirements for a thermistor (PTC) depend on the amount of electromagnetic energy it absorbs, i.e. stored in the field winding before de-excitation is initiated. Accordingly, the more electromagnetic energy stored in the field winding, the higher the temperature range requirements set for the thermistor (PTC) and, conversely, the lower.
The non-linear demagnetization resistor in the demagnetization circuit is a zinc oxide resistor and a silicon carbide resistor respectively, and can be set according to the type and application occasion of a synchronous motor, the zinc oxide resistor has switching characteristics, has small leakage current and can be directly connected in parallel with two ends of a rotor winding, but the characteristics of the zinc oxide resistor change greatly along with the extension of time, the damaged zinc oxide resistor is in a short-circuit state and also threatens the safe operation of a generator, the zinc oxide resistor with a high voltage threshold value matched with the zinc oxide resistor is difficult to select along with the increase of the capacity of the generator, the volt-ampere characteristic of the silicon carbide resistor is between the linear resistor and the zinc oxide resistor, the demagnetization time is between the linear resistor and the zinc oxide resistor, the zinc oxide resistor and the silicon carbide resistor have the advantages of the linear resistor and the zinc oxide resistor, the characteristics are stable, the silicon carbide resistor has no obvious threshold value voltage.
Referring to fig. 2, as embodiment 2 of the present invention, a synchronous generator rotor overvoltage protection circuit is added, the rotor overvoltage protection circuit includes a thyristor, the thyristor is connected in parallel with a thermistor, the thyristor is connected with an overvoltage trigger, the overvoltage trigger is connected with two ends of a synchronous generator excitation winding, and the rotor overvoltage protection is mainly used for preventing overvoltage introduced from a thyristor rectifying device side and overvoltage introduced from a generator side, so as to protect a generator rotor and an excitation device themselves.
In the description herein, references to the description of "one embodiment," "an example," "a specific example," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.
The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art should be considered to be within the technical scope of the present invention, and the technical solutions and the inventive concepts thereof according to the present invention should be equivalent or changed within the scope of the present invention.
In this disclosure, aspects of the present invention are described with reference to the accompanying drawings, in which a number of illustrative embodiments are shown. Embodiments of the present disclosure are not necessarily defined to include all aspects of the invention. It should be appreciated that the various concepts and embodiments described above, as well as those described in greater detail below, may be implemented in any of numerous ways, as the disclosed concepts and embodiments are not limited to any one implementation. In addition, some aspects of the present disclosure may be used alone, or in any suitable combination with other aspects of the present disclosure.
The preferred embodiments of the invention disclosed above are intended to be illustrative only. The preferred embodiments are not intended to be exhaustive or to limit the invention to the precise forms disclosed. Obviously, many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the invention and the practical application, to thereby enable others skilled in the art to best utilize the invention. The invention is limited only by the claims and their full scope and equivalents.
Claims (4)
1. The utility model provides a synchronous generator deexcitation circuit based on thermistor, includes generator rectifier circuit, magnetic field circuit breaker and synchronous generator excitation winding, its characterized in that: the excitation winding of the synchronous generator is also connected with a field suppression circuit in parallel, the field suppression circuit comprises a thermistor and a nonlinear field suppression resistor, and the thermistor and the nonlinear field suppression resistor are connected in series.
2. The thermistor-based synchronous generator demagnetization circuit of claim 1, characterized in that: the nonlinear field suppression resistor is a zinc oxide (ZnO) field suppression resistor.
3. The thermistor-based synchronous generator demagnetization circuit of claim 1, characterized in that: the nonlinear field suppression resistor is a silicon carbide (SiC) field suppression resistor.
4. The thermistor-based synchronous generator demagnetization circuit of claim 1, characterized in that: the de-excitation circuit further comprises a rotor overvoltage protection circuit, the rotor overvoltage protection circuit comprises a thyristor, the thyristor is connected with the thermistor in parallel, one end of the thyristor is connected with an overvoltage trigger, and the overvoltage trigger is connected with two ends of the excitation winding of the synchronous generator.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010794347.3A CN111884551A (en) | 2020-08-10 | 2020-08-10 | Synchronous generator de-excitation circuit based on thermistor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010794347.3A CN111884551A (en) | 2020-08-10 | 2020-08-10 | Synchronous generator de-excitation circuit based on thermistor |
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| Publication Number | Publication Date |
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| CN111884551A true CN111884551A (en) | 2020-11-03 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202010794347.3A Pending CN111884551A (en) | 2020-08-10 | 2020-08-10 | Synchronous generator de-excitation circuit based on thermistor |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115083705A (en) * | 2022-06-21 | 2022-09-20 | 深圳可雷可科技股份有限公司 | Silicon carbide nonlinear resistor for de-excitation of generator |
-
2020
- 2020-08-10 CN CN202010794347.3A patent/CN111884551A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115083705A (en) * | 2022-06-21 | 2022-09-20 | 深圳可雷可科技股份有限公司 | Silicon carbide nonlinear resistor for de-excitation of generator |
| CN115083705B (en) * | 2022-06-21 | 2023-03-24 | 深圳可雷可科技股份有限公司 | Silicon carbide nonlinear resistor for de-excitation of generator |
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