Voltage-frequency ratio limiting and setting method and device for overvoltage protection of phase modulator
阅读说明：本技术 用于调相机过电压保护的压频比限制整定方法及装置 (Voltage-frequency ratio limiting and setting method and device for overvoltage protection of phase modulator ) 是由 许国瑞 李志强 夏潮 曹志伟 王继豪 李睿智 于 2021-09-30 设计创作，主要内容包括：本发明涉及一种用于调相机过电压保护的压频比限制整定方法及装置,当调相机压频比等于压频比低定值K-(1)时,设定调相机继电器保护装置的第一动作时间T-(1),所述压频比低定值K-(1)为调相机最大励磁电流所对应的压频比；当调相机压频比等于或大于压频比高定值K-(2)时,设定调相机继电器保护装置的第二动作时间T-(2),压频比高定值K-(2)为调相机定子绕组绝缘击穿电压对应的压频比；当调相机压频比大于压频比低定值K-(1),且小于压频比高定值K-(2)时,调相机继电器保护装置的第三动作时间T-(3)根据反时限过电压曲线确定。本发明能够在保障机组安全的情况下,最大限度发挥调相机的动态无功支撑能力。(The invention relates to a voltage-frequency ratio limiting and setting method and a device for over-voltage protection of a phase modulator, when the voltage-frequency ratio of the phase modulator is equal to the low constant value K of the voltage-frequency ratio 1 Setting a first action time T of a phase modulator relay protection device 1 Said pressure-frequency ratio is lower than a constant value K 1 The voltage-frequency ratio corresponding to the maximum exciting current of the phase modulator; when the pressure-frequency ratio of the phase modulator is equal to or greater than the constant value K of the pressure-frequency ratio 2 Setting a second action time T of a phase modulator relay protection device 2 Constant value of voltage-to-frequency ratio K 2 The voltage-frequency ratio is corresponding to the insulation breakdown voltage of the phase modulator stator winding; when the pressure-frequency ratio of the phase modulator is larger than the pressure-frequency ratio, the lower constant value K is adopted 1 And is less than pressureHigh frequency ratio constant value K 2 Third action time T of phase modulator relay protection device 3 And determining according to an inverse time limit overvoltage curve. The dynamic reactive power support system can furthest exert the dynamic reactive power support capability of the phase modulator under the condition of ensuring the safety of the unit.)
1. A voltage-frequency ratio limiting and setting method for over-voltage protection of a phase modulator is characterized in that,
when the phase modulator voltage-frequency ratio is equal to the voltage-frequency ratio low constant value K1Setting a first action time T of a phase modulator relay protection device1Said pressure-frequency ratio is lower than a constant value K1The voltage-frequency ratio corresponding to the maximum exciting current of the phase modulator;
when the pressure-frequency ratio of the phase modulator is equal to or greater than the constant value K of the pressure-frequency ratio2Setting a second action time T of a phase modulator relay protection device2Constant value of voltage-to-frequency ratio K2The voltage-frequency ratio is corresponding to the insulation breakdown voltage of the phase modulator stator winding;
when the pressure-frequency ratio of the phase modulator is larger than the pressure-frequency ratio, the lower constant value K is adopted1And is less than the constant value K of the voltage-frequency ratio2Determining the third action time T of the phase modulator relay protection device according to the inverse time limit overvoltage curve3。
2. The voltage-to-frequency ratio limit setting method for overvoltage protection of a phase modulator according to claim 1, characterized in that: the inverse time-lag overvoltage curve has a low fixed value K according to the voltage-frequency ratio1First action time T1Constant value K of voltage-frequency ratio2Second operation time T2And (4) obtaining.
3. The voltage-to-frequency ratio limit setting method for overvoltage protection of a phase modulator according to claim 1, characterized in that: second action time T2Less than the first action time T1(ii) a Third action time T3Greater than the second action time T2And is less than the first action time T1。
4. The voltage-to-frequency ratio limit setting method for overvoltage protection of a phase modulator according to claim 1, characterized in that: the first action time T1 is longer than the time required for the phase modulator to adjust the strong excitation current.
5. The voltage-to-frequency ratio limit setting method for overvoltage protection of a phase modulator according to claim 1, characterized in that: pressure-frequency ratioLow constant value K1Is obtained by a process which comprises the steps of,
excitation current IfAnd the pressure-frequency ratio K satisfies the following conditions:
wherein Q is reactive power, QNRated reactive power, U is terminal voltage, and f is frequency; f (I)f) Is an exciting current IfA functional relation with the voltage-to-frequency ratio K;
in the formula If_maxThe maximum exciting current of the phase modulator which can be operated for a long time.
6. The voltage-to-frequency ratio limit tuning method for overvoltage protection of a phase modulator according to claim 1 or 2, characterized in that: the inverse time-limited overvoltage curve is obtained by the following formula,
in the formula, m and n are coefficients, K is a voltage-frequency ratio, and t is the action time of the relay protection device; lowering the pressure-frequency ratio by a constant value K1First action time T1Constant value K of voltage-frequency ratio2Second operation time T2Substituting the formula to obtain the coefficient m, n.
7. The voltage-to-frequency ratio limit setting method for overvoltage protection of a phase modulator according to claim 1, characterized in that: when the pressure-frequency ratio of the phase modulator is larger than the pressure-frequency ratio, the lower constant value K is adopted1And is less than the constant value K of the voltage-to-frequency ratio2And adjusting to reduce the exciting current of the phase modulator.
8. The voltage-to-frequency ratio limit setting method for overvoltage protection of a phase modulator according to claim 1, characterized in that: low constant value K of pressure-frequency ratio1The value is 1.15-1.18, the first action time T1The value is 18 s-22 s.
9. The voltage-to-frequency ratio limit setting method for overvoltage protection of a phase modulator according to claim 1, characterized in that: constant value K of voltage-frequency ratio2The value is 1.28-1.32, and the second action time T2The value is 0.5 s-0.7 s.
10. A voltage-to-frequency ratio limiting and tuning apparatus for overvoltage protection of a phase modulator, characterized by being adapted to perform the method of any one of claims 1 to 9.
Technical Field
The invention relates to a voltage-frequency ratio limiting and setting method and a device for overvoltage protection of a phase modulator.
Background
With the development of extra-high voltage direct current transmission, a novel high-capacity phase modulator is gradually applied to a direct current converter station to provide reactive support for a system. Compared with the traditional unit, the dynamic characteristic, overload capacity and the like of the novel phase modulator are greatly improved, and a corresponding control protection strategy is formulated according to the actual capacity of the novel phase modulator in order to fully exert the dynamic reactive power supporting capacity of the novel phase modulator. However, the control protection configuration of the current phase modulator still continues to use the traditional generator protection configuration, which on one hand results in that the dynamic reactive performance of the phase modulator cannot be fully exerted, and on the other hand may result in that individual protection is difficult to start, thus bringing potential threat to the phase modulator. For example, the new synchronous phase modulator definitely requires the phase modulator to operate at a higher rated voltage for a long time at the beginning of technical specification establishment, but the limitation of the voltage-frequency ratio still adopts a limit value of 1.07. Therefore, the configuration for performing phase modulator overvoltage protection is necessary for guaranteeing the safety of the unit and exerting the dynamic reactive power supporting capability of the unit to the maximum extent based on the actual reactive power capability of the phase modulator.
Disclosure of Invention
The invention aims to provide a voltage-frequency ratio limiting and setting method and device for over-voltage protection of a phase modulator, which can exert the dynamic reactive power supporting capability of the phase modulator to the maximum extent under the condition of ensuring the safety of a unit.
Based on the same inventive concept, the invention has two independent technical schemes:
1. a method for limiting and setting the voltage-frequency ratio of over-voltage protection of phase modulator features that when the voltage-frequency ratio of phase modulator is equal to the lower constant value K of voltage-frequency ratio1Setting a first action time T of a phase modulator relay protection device1Said pressure-frequency ratio is lower than a constant value K1The voltage-frequency ratio corresponding to the maximum exciting current of the phase modulator;
when the pressure-frequency ratio of the phase modulator is equal to or greater than the constant value K of the pressure-frequency ratio2Setting a second action time T of a phase modulator relay protection device2Constant value of voltage-to-frequency ratio K2The voltage-frequency ratio is corresponding to the insulation breakdown voltage of the phase modulator stator winding;
when the pressure-frequency ratio of the phase modulator is larger than the pressure-frequency ratio, the lower constant value K is adopted1And is less than the constant value K of the voltage-frequency ratio2When the temperature of the water is higher than the set temperature,
determining a third action time T of the phase modulator relay protection device according to the inverse time limit overvoltage curve3。
Further, the inverse time-lag overvoltage curve has a low fixed value K according to the voltage-frequency ratio1First action time T1Constant value K of voltage-frequency ratio2Second operation time T2And (4) obtaining.
Further, the second action time T2Less than the first action time T1(ii) a Third action time T3Greater than the second action time T2Is less than the first action time T1。
Further, the first action time T1Is longer than the time required by the phase modulator to adjust the strong exciting current.
Further, the voltage-to-frequency ratio is low by a constant value K1Is obtained by a process which comprises the steps of,
excitation current IfAnd the pressure-frequency ratio K satisfies the following conditions:
wherein Q is reactive power, QNRated reactive power, U is terminal voltage, and f is frequency; f (I)f) Is an exciting current IfA functional relation with the voltage-to-frequency ratio K;
in the formula If_maxThe maximum exciting current of the phase modulator which can be operated for a long time.
Further, the inverse time-limited overvoltage curve is obtained by the following formula,
in the formula, m and n are coefficients, and t is the action time of the relay protection device; lowering the pressure-frequency ratio by a constant value K1First action time T1Constant value K of voltage-frequency ratio2Second operation time T2Substituting the formula to obtain the coefficient m, n.
Further, when the pressure-frequency ratio of the phase modulator is larger than the pressure-frequency ratio, the lower constant value K is adopted1And is less than the constant value K of the voltage-to-frequency ratio2And adjusting to reduce the exciting current of the phase modulator.
Further, the voltage-to-frequency ratio is low by a constant value K1The value is 1.15-1.18, the first action time T1The value is 18 s-22 s.
Further, the voltage-to-frequency ratio is high in constant value K2The value is 1.28-1.32, and the second action time T2The value is 0.5 s-0.7 s.
2. A voltage-frequency ratio limiting and setting device for overvoltage protection of a phase modulator is used for executing the method.
The invention has the following beneficial effects:
the invention takes the voltage-frequency ratio as the setting basis of the overvoltage protection, can be well matched with a relay protection device of a phase modulator to realize the overvoltage protection, and can exert the dynamic reactive power supporting capability of the phase modulator to the maximum extent under the condition of ensuring the safety of a unit.
When the pressure-frequency ratio of the phase modulator is equal to or greater than the pressure-frequency ratio constant value K2Setting a second action time T of a phase modulator relay protection device2Constant value of voltage-to-frequency ratio K2A second action time T corresponding to the voltage-frequency ratio of insulation breakdown voltage of stator winding of phase modulator2The action time of the phase modulator is short, and the phase modulator is guaranteed to be reliably protected.
When the pressure-frequency ratio of the phase modulator is equal to the low constant value K of the pressure-frequency ratio1Setting a first action time T of a phase modulator relay protection device1Said pressure-frequency ratio is lower than a constant value K1The voltage-frequency ratio corresponding to the maximum exciting current which can be operated for a long time by the phase modulator; when the pressure-frequency ratio of the phase modulator is larger than the pressure-frequency ratio, the lower constant value K is adopted1And is less than the constant value K of the voltage-to-frequency ratio2Third action time T of phase modulator relay protection device3And determining according to an inverse time limit overvoltage curve. Second action time T2And a third action time T3The action time is long, and when the phase modulation machine overexcitation time is short, the relay protection device can not act, so that the false operation of the relay protection device is effectively prevented, and the dynamic reactive power support capability of the phase modulation machine is exerted to the maximum extent under the condition of ensuring the safety of the machine set.
Drawings
FIG. 1 is a schematic diagram of voltage to frequency ratio as a function of field current;
fig. 2 is an inverse time-limited overvoltage curve.
Detailed Description
The present invention is described in detail with reference to the embodiments shown in the drawings, but it should be understood that these embodiments are not intended to limit the present invention, and those skilled in the art should understand that functional, methodological, or structural equivalents or substitutions made by these embodiments are within the scope of the present invention.
The first embodiment is as follows:
voltage-frequency ratio limiting and setting method for overvoltage protection of phase modulator
When the phase modulator voltage-frequency ratio is equal to the voltage-frequency ratio low constant value K1Setting a first action time T of a phase modulator relay protection device1Said pressure-frequency ratio is lower than a constant value K1The voltage-frequency ratio corresponding to the maximum exciting current which can be operated for a long time by the phase modulator.
Low constant value K of pressure-frequency ratio1Is obtained by a process which comprises the steps of,
excitation current IfAnd the pressure-frequency ratio K satisfies the following conditions:
wherein Q is reactive power, QNRated reactive power, U is terminal voltage, and f is frequency; f (I)f) Is an exciting current IfA functional relation with the voltage-to-frequency ratio K;
in the formula If_maxThe maximum exciting current of the phase modulator which can be operated for a long time.
As shown in fig. 1, when the synchronous phase modulator outputs rated reactive power, different voltage-to-frequency ratios are provided for different exciting currents. The law that the voltage-frequency ratio changes with the exciting current when the synchronous phase modulator outputs rated reactive power is obtained through calculation, and the following table shows. It can be seen from the table that as the voltage-to-frequency ratio increases, the exciting current is increased continuously in order to keep the output reactive power of the synchronous phase modulator constant. Under the rated excitation current of 1.1 times that of the long-term operation, the voltage-frequency ratio can reach 1.17.
TABLE 1 law of variation of voltage-to-frequency ratio with exciting current under rated reactive power
Low constant value K of pressure-frequency ratio1The value is 1.15-1.18, in this example, K1Value 1.17, first action time T1Is longer than the time needed by the phase modulator to regulate the strong exciting current and the first action time T1The value is 18 s-22 s, and in the embodiment, the first action time T1The value is 20 s.
When the pressure-frequency ratio of the phase modulator is equal to or greater than the constant value K of the pressure-frequency ratio2Setting a second action time T of a phase modulator relay protection device2Constant value of voltage-to-frequency ratio K2The voltage-frequency ratio is corresponding to the insulation breakdown voltage of the phase modulator stator winding.
Constant value K of voltage-frequency ratio2The value is 1.28-1.32, in this example, K2Value of 1.3, second action time T2The value is 0.5 s-0.7 s, and in the embodiment, the second action time T2The value was 0.6 s.
When the pressure-frequency ratio of the phase modulator is larger than the pressure-frequency ratio, the lower constant value K is adopted1And is less than the constant value K of the voltage-to-frequency ratio2Third action time T of phase modulator relay protection device3And determining according to an inverse time limit overvoltage curve.
In this embodiment, when the phase modulator voltage-to-frequency ratio K is greater than 1.17 and less than 1.3, the third action time T of the relay protection device is determined according to the inverse time-lag overvoltage curve3。
The inverse time-lag overvoltage curve has a low fixed value K according to the voltage-frequency ratio1First action time T1Constant value K of voltage-frequency ratio2Second operation time T2And (4) obtaining. Second action time T2Less than the first action time T1(ii) a Third action time T3Greater than the second action time T2Is less than the first action time T1。
The inverse time-limited overvoltage curve is obtained by the following formula,
in the formula, m and n are coefficients, and t is the action time of the relay protection device; lowering the pressure-frequency ratio by a constant value K1First action time T1Constant voltage-frequency ratioValue K2Second operation time T2Substituting the formula to obtain the coefficient m, n. In this example, K is1Value 1.17, first action time T1The value is 20s, K2Value of 1.3, second action time T2Substituting the value of 0.6s into the formula can obtain the coefficients m, n are 34.59 and 27 respectively. The formula is as follows:
thereby, an inverse time-lag overvoltage curve (a relation curve between the compression ratio and the operation time) is obtained as shown in fig. 2.
When the pressure-frequency ratio of the phase modulator is larger than the pressure-frequency ratio, the lower constant value K is adopted1And is less than the constant value K of the voltage-to-frequency ratio2And adjusting to reduce the exciting current of the phase modulator.
Example two:
voltage-frequency ratio limiting and setting device for overvoltage protection of phase modulator
The setting device is used for executing the method.
The above-listed detailed description is only a specific description of a possible embodiment of the present invention, and they are not intended to limit the scope of the present invention, and equivalent embodiments or modifications made without departing from the technical spirit of the present invention should be included in the scope of the present invention.
It will be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrative embodiments, and that the present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.
- 上一篇：一种医用注射器针头装配设备
- 下一篇：飞行器启动和发电系统