KR20220068521A - Torque Coefficient Calculation Method - Google Patents

Abstract

The present invention relates to a method for quickly calculating a torque coefficient through detection of a vibration component. Provided is a method for quickly calculating a torque coefficient by deriving only a vibration component for changing an angular velocity and torque of a generator through a controller capable of filtering a specific frequency region without fast Fourier transform. Since the number of data storage and output data capacity are consumed less, the computer performance and storage capacity are less affected. In addition, before a special facility is installed in a power system, the stability of the power system could be improved by verifying in advance whether a mutual distortion phenomenon occurs between a generator in the power system and the special facility such as a series compensator, a high-voltage direct current (HVDC), or the like.

Description

Torque Coefficient Calculation Method

The present invention relates to a method and an arithmetic device capable of quickly calculating a torque coefficient through detection of a vibration component of a generator and a generator rotating shaft.

Conventionally, a method for calculating the complex torque coefficient is to model a system including a turbine generator and special equipment in an EMT simulation environment, and generate random vibrations corresponding to a specific frequency in the turbine generator to determine the angular velocity of the generator, electrical After storing data such as torque and frequency, it was a fast Fourier transform method of data (angular velocity, electrical torque, frequency, etc.) obtained from EMT simulation. However, there is a problem in that computer performance and additional calculation tools are required because torque coefficients must be discretely derived through a tool necessary for storing a significant amount of data and processing the stored data for a fast Fourier transform. Therefore, the present invention has been devised to solve the above problems, and it is an object of the present invention to reduce the data storage and calculation steps in calculating the complex torque coefficient and to derive the results on the EMT simulation.

Laid-open Patent Publication No. 10-2018-0086628 (2018.08.01.)

Accordingly, the present invention aims to provide a method capable of quickly calculating a torque coefficient by deriving only a vibration component that changes the angular velocity of the generator rotation shaft and the electrical torque of the generator through a controller capable of filtering a specific frequency region without a fast Fourier transform do it with

In order to achieve the above object, (S1) a first to change any one or more of the angular velocity and the electrical torque of the generator to the rotating shaft included in the generator in the generator model of the power system modeled to output the angular velocity and torque as an electrical signal injecting a signal; (S2) outputting any one or more of the angular velocity and the electrical torque changed by the step (S1); (S3) passing the value output in step (S2) through a first filter to detect a vibration component by the first signal; and (S4) calculating a torque coefficient using the vibration component detected in step (S3). A method for calculating coefficients is provided.

In addition, as a device for calculating a torque coefficient of a modeled power system, the device includes an input unit, a calculation unit, and an output unit, and the calculation unit (S1) In the model of the generator on the power system modeled to output the angular velocity and torque as an electrical signal injecting a first signal for changing at least one of the angular velocity and the electrical torque of the generator to the rotation shaft included in the generator; (S2) outputting any one or more of the angular velocity and the electrical torque changed by the step (S1); (S3) passing the value output in step (S2) through a first filter to detect a vibration component by the first signal; and (S4) calculating a torque coefficient by using the vibration component detected in the step (S3), wherein the calculating unit determines the stability of the power system from the calculated torque coefficient. It provides an arithmetic unit.

The torque coefficient calculation method according to the present invention is calculated by deriving and calculating the vibration component that causes the angular velocity and electric torque to vibrate and diverge from the output value of the generator, so the calculation step for calculating the torque coefficient is simplified and can be quickly derived.

In addition, compared to the conventional fast Fourier transform method, the number of data storage and output data capacity are consumed less, so that the computer performance and storage capacity are less affected.

In addition, it is possible to verify in advance whether or not the occurrence of mutual distortion between the generator and the special equipment such as the series compensator and HVDC in the electric power system before the special equipment is installed in the electric power system, the stability of the electric power system system can be improved. .

1 shows the modeling of the power system for calculating the torque coefficient of the present invention.
Figure 2 shows a flowchart for the torque coefficient calculation method of the present invention.
Figure 3 shows the axis of rotation between the turbine and the generator to which the first signal is injected.
4 is a graph showing the change in the angular velocity of the rotation shaft between the generator and the turbine to which the first signal is injected.
5 is a graph showing a change in electrical torque of the generator after the first signal is injected into the rotation shaft between the generator and the turbine.
6 shows a first filter for detecting a vibration component from the output of the generator.
7 shows a method of changing a phase of a detected vibration component through a low-pass filter.
8 is a graph showing the phase of the detected vibration component is changed on a complex plane.
9 shows the values of the torque coefficient according to the change in the frequency of the first signal.
10 is a table comparing the data storage number and output data capacity of the fast Fourier transform methodology and the torque coefficient calculation method of the present invention.
11 shows the configuration of the torque coefficient calculating device.

The invention to be described below can have various changes and can have various embodiments, and specific embodiments are illustrated in the drawings and described in detail. However, this is not intended to limit the invention described below to specific embodiments, and it should be understood to include all modifications, equivalents, and substitutes included in the spirit and scope of the technology described below.

1 to 10 show data for explaining the method for calculating the complex torque coefficient of the present invention. Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings to help the understanding of the present invention. However, the following examples are only provided for easier understanding of the present invention, and the contents of the present invention are not limited by the following examples.

1 shows a modeling of a power system including a generator in the torque coefficient calculation method according to the present invention. Referring to FIG. 1 , the mutual torsion of the differential, which is one of the resonance phenomena of the differential, means a problem occurring between the turbine generator and special equipment such as a series compensator and HVDC in the power system. Here, the differential resonance phenomenon refers to a phenomenon in which the vibration of the shaft between the turbine and the generator is amplified under specific operating conditions due to the interaction between the power system and the generator. The specific operating condition refers to a condition in which the power system to which the generator is connected according to the disturbance of the system includes a resonance frequency component of a value smaller than the commercial frequency. In particular, when the generator is connected to a long-distance power transmission line compensated by a series capacitor, it is vulnerable to a differential resonance phenomenon, and at this time, the amplification of the vibration torque induced in the shaft between the turbine and the generator may cause fatigue and damage of the shaft.

With regard to the occurrence of the problem, the power system system is designed to easily verify whether the problem can occur between the generator and the special equipment in the planning stage before special equipment such as series capacitors, FACTS, HVDC, etc. are installed in the electric power system. By modeling, the system configuration by linking the generator and the series compensation facility and the simulation environment for each system operation situation were constructed. The simulation environment was modeled using PSCAD/EMTDC, a power system analysis program, and simulation was performed through this.

2 is a flowchart illustrating a method for calculating a torque coefficient according to the present invention. Referring to FIG. 2, the torque coefficient calculation method according to the present invention (S1) is the angular velocity and the electrical power of the generator on the rotating shaft included in the generator in the generator model of the power system modeled to output the angular velocity and torque as electrical signals. injecting a first signal for changing any one or more of the torques; (S2) outputting any one or more of the angular velocity and the electrical torque changed by the (S1) step; (S3) the (S2) step detecting a vibration component by the first signal by passing the output value through a first filter; and (S4) calculating a torque coefficient using the vibration component detected in step (S3).

)는 하기의 수학식(1)으로 표현될 수 있다.When the first signal is injected, the electric torque deviation (

) can be expressed by the following Equation (1).

수학식(1)

Equation (1)

3 shows a position where the first signal is injected. Referring to FIG. 3 , the first signal may be injected into the rotation shaft of the generator or the rotation shaft between the turbine and the generator to change the angular velocity of the rotation shaft.

4 is a graph showing the angular velocity versus time of the rotation shaft after the first signal is injected into the rotation shaft between the turbine and the generator. Referring to FIG. 4 , the first signal may be injected into a rotating shaft between a generator and a turbine that outputs angular velocity and torque as electrical signals. The rotation shaft between the generator and the turbine may maintain a constant electrical torque output from the generator before the first signal is injected, but when the first signal is injected into the rotation shaft between the generator and the turbine, vibration occurs in the rotation shaft This may cause a change in the electrical torque of the generator. The first signal is a perturbation signal that is disturbed by changing the electrical torque of the generator, and may be injected into the rotation shaft in a divergent type in which the amplitude of the angular velocity gradually increases with time.

)를 만든 후 미분기를 통과시켜 각속도에 대한 미소 신호(

)를 만들어 상기 미소 신호가 포함된 새로운 각속도(

)로 주입된다. 상기 제1 신호는 발전기와 터빈 사이의 회전축에 주입되어 발전기의 전기적 토크 편차 및 각속도 편차가 발생시킬 수 있다.The first signal is a minute signal for an angle (

) and pass it through a differentiator to obtain a microsignal (

) to create a new angular velocity (

) is injected. The first signal may be injected into the rotation shaft between the generator and the turbine to generate an electrical torque deviation and an angular velocity deviation of the generator.

5 is a graph showing the electrical torque versus time of the electrical torque output from the turbine. Referring to FIG. 5 , when the first signal is injected into the rotation shaft between the generator and the turbine, a change occurs in the electrical torque signaled by the torque output from the generator. Although the electrical torque of the generator is maintained constant before the signal is injected, the graph may appear in the form of a divergent type in which the amplitude of the electrical torque gradually increases after the first signal is injected.

)의 변화가 발생하게 되며, 상기 전기적 토크는 토크 평균(

)과 진동 성분(

)으로 나타낼 수 있다. 전기적 토크 편차(

)는 전기적 토크(

)와 토크 평균(

)의 차에 해당된다. 상기 전기적 토크 편차(

)는 하기의 수학식과 같이 표현될 수 있다. Since the electrical torque output from the generator includes a vibration component generated by the vibration of the shaft by the first signal, it is necessary to detect only the vibration component. Electrical torque of the generator (

) occurs, and the electrical torque is the torque average (

) and the vibration component (

) can be expressed as electrical torque deviation (

) is the electrical torque (

) and the torque average (

) corresponds to the car of The electrical torque deviation (

) can be expressed as the following equation.

수학식(2)

Equation (2)

수학식(3)

Equation (3)

)는 복소평면에 하기의 수학식과 같이

와

로 표현될 수 있다.The electrical torque deviation (

) is in the complex plane as in the following equation

Wow

can be expressed as

수학식(4)

Equation (4)

수학식(5)

Equation (5)

6 illustrates a process of detecting a vibration component by passing an electrical torque and an angular velocity output from the generator through a first filter. Referring to FIG. 6 , the angular velocity output from the generator may be integrated to form an angle, and the angular deviation may be obtained by passing it through the first filter.

In addition, in order to detect a vibration component having a frequency of a certain range or more in the electrical torque output from the generator, the angular velocity and the electrical torque output from the generator are combined with a high pass filter and a band pass filter in series. It can pass through the first filter connected to

The high-pass filter may be a first-order or second-order filter, and the band-pass filter may also be a first-order or second-order filter.

) 뿐만 아니라 토크 평균(

) 성분도 일부 포함될 수 있다.By connecting the high pass filter and the band pass filter in series with each other, the accuracy of detecting the vibration component may be further increased. If only one of the high-pass filter and the band-pass filter is used, the detected component is added to the vibration component (

) as well as the torque average (

) may also be included.

An object of the present invention is to determine whether a differential mutual torsion phenomenon, which is one of differential resonance phenomena occurring between a generator, a series compensator, and special equipment such as HVDC, occurs in a modeled power system. Since the differential resonance phenomenon refers to a state in which an arbitrary generator and the rest of the power system exchange energy at single or multiple frequencies below a specified frequency such as 50Hz or 60Hz, the power system modeled in the frequency domain below 60Hz It can be determined whether a differential mutual torsion phenomenon occurs between the generator and special equipment. Therefore, it is possible to determine whether the twisting phenomenon occurs by inputting a specified frequency of 60 Hz or less to the high-pass filter and the band-pass filter to calculate the torque coefficient.

7 shows a method of changing the phase by 90° by passing the detected vibration component through the second filter low-pass filter, and FIG. A method for obtaining the magnitude and phase of a component is shown. 7 and 8, the vibration component includes an angular deviation of the rotation shaft that is changed by the first signal and an electrical torque deviation of the generator that is changed by the first signal, and the detected In order to obtain the magnitude and phase of the vibration component on a complex plane, the electric torque deviation and angle deviation output from the generator are passed through a low pass filter, which is a second filter, to change the phase by 90° ((S5) step). The electric torque deviation and angular deviation passing through the low-pass filter may be represented on an imaginary axis on a complex plane, and the electrical torque deviation and angular deviation before passing through the low-pass filter may be indicated on a real axis on the complex plane, so that the electrical torque It is possible to obtain the phase and magnitude of the deviation and the angle deviation (step S6).

The frequency input to the low-pass filter is also input to a frequency of 60 Hz or less, which is to be determined whether the mutual distortion phenomenon of the differential occurs. The input frequency is input as the same value for the high-pass filter, the band-pass filter, and the low-pass filter.

와

는 전기적 토크 편차의 위상 및 크기를 통해 하기의 수학식으로 산정할 수 있다.

Wow

can be calculated by the following equation through the phase and magnitude of the electrical torque deviation.

수학식(6)

Equation (6)

수학식(7)

Equation (7)

수학식(8)

Equation (8)

와

를 통해 댐핑 토크 계수(

) 및 동기 토크 계수(

)를 연산할 수 있다. 상기 댐핑 토크 계수 및 동기 토크 계수는 하기의 수학식과 같이 표현될 수 있다.calculated

Wow

damping torque coefficient (

) and synchronous torque coefficient (

) can be calculated. The damping torque coefficient and the synchronous torque coefficient may be expressed as follows.

수학식(9)

Equation (9)

수학식(10)

Equation (10)

수학식(11)

Equation (11)

Substituting the angular deviation and the angular velocity deviation into Equation (9), it can be expressed as Equation (12) below.

수학식(12)

Equation (12)

수학식(13)

Equation (13)

) 및 동기 토크 계수(

)는 하기의 수학식(15) 및 수학식(16)으로 산정할 수 있다((S7) 단계).damping torque coefficient (

) and synchronous torque coefficient (

) can be calculated by the following Equations (15) and (16) (step S7).

수학식(14)

Equation (14)

수학식(15)

Equation (15)

수학식(16)

Equation (16)

수학식(17)

Equation (17)

) 및 동기 토크 계수(

)가 있고, 이 중 상기 댐핑 토크 계수(

)는 평형상태를 벗어나 진동하는 전기적 토크가 발산하는 것을 감쇠하여 다시 평형상태로 할 수 있는 능력이 있는지 즉, 안정도가 확보된 시스템인지 아닌지를 판단할 수 있도록 하는 계수이다. The stability of the power system refers to the ability of the power system to return to the balanced operating state in the event of disturbance in a given initial operating condition. The stability of such a power system can be determined by calculating the torque coefficient. The torque coefficient can determine whether there is an ability to return the vibration of the electric torque of the generator out of the balanced operation state due to the disturbance to the electric torque range within the balanced operation state. The torque coefficient includes the damping torque coefficient (

) and synchronous torque coefficient (

), of which the damping torque coefficient (

) is a coefficient that allows it to be judged whether the system has the ability to return to the equilibrium state by damping the dissipation of the oscillating electrical torque out of the equilibrium state, that is, whether the system is stable or not.

) 의 부호가 양수 또는 0인 경우, 발전기 회전축에 발생 되는 진동 성분을 감쇠시켜 초기의 평형상태로 되돌릴 수 있다는 것을 의미하고, 음수인 경우 상기 발전기 회전축에 발생 되는 진동 성분을 감쇠시킬 수 있는 능력이 없어 발산시킬 수 있는 구성이다. 도 9를 참조하면, 주파수의 변화에 따라 댐핑 토크 계수(

) 및 동기 토크 계수(

)의 값이 변화하는데 특정한 주파수의 범위에서 상기 댐핑 토크 계수(

) 및 동기 토크 계수(

) 부호가 음수에 해당되는 언더 슈트가 발생하였으므로, 상기 특정 주파수 범위에서 발전기와 특수설비 사이에 안정도는 불안정하여 문제가 발생할 수 있다는 것을 나타낸다. 상기 특정 주파수 범위 내의 진동 성분이 유입된다면 발전기의 전기적 토크는 상기의 진동 성분을 감쇠하여 다시 평형상태로 되돌릴 수 없고 전기적 토크가 발산하게 하므로 결국 상기 발전기와 특수설비 사이에 문제가 발생될 수 있다는 것을 예측할 수 있다. 9 is a graph showing changes in values of a damping torque coefficient and a synchronous torque coefficient according to a continuous frequency change of the first signal. Calculated damping torque coefficient (

), if the sign is positive or 0, it means that the vibration component generated on the generator rotation shaft can be attenuated and returned to the initial equilibrium state, and when it is negative, the ability to attenuate the vibration component generated on the generator rotation shaft is It is a composition that can be diffused without it. Referring to FIG. 9 , the damping torque coefficient (

) and synchronous torque coefficient (

) changes in the damping torque coefficient (

) and synchronous torque coefficient (

) sign corresponds to a negative number, so it indicates that the stability between the generator and the special equipment is unstable in the specific frequency range and may cause problems. If the vibration component within the specific frequency range is introduced, the electrical torque of the generator attenuates the vibration component and cannot be returned to the equilibrium state again, and the electrical torque is emitted. predictable.

In simulation using PSCAD/EMTDC power system analysis program, both discrete and continuous results can be obtained, so computer performance and storage capacity are not significantly affected. 10 is a table comparing the data capacity of data obtained to use the fast Fourier transform and the result finally derived through the present invention. The fast Fourier transform methodology and the torque coefficient calculation method of the present invention can confirm a clear difference in the number and capacity of data. The present invention reduces the data storage and calculation steps in the torque coefficient calculation process, and the results can be obtained immediately in the simulation, so that the results are easier and faster than the case of calculating the torque coefficient using the fast Fourier transform method. can be derived

If the torque coefficient calculation method according to the present invention is used, the distortion problem occurring between the generator and the series compensator, HVDC, series capacitor, TCSC (Thyristor Controlled Series Capacitor) and STATCOM (Static Synchronous Compensator), etc. is possible can be determined in advance by calculating the torque coefficient before the special equipment is installed in the power system.

11 relates to a torque coefficient calculating device according to the present invention.

The arithmetic unit may include an input unit, an arithmetic unit, and an output unit. The calculation unit is performed including the steps (S1), (S2), (S3) and (S4), and the calculation unit (S1) is modeled to output angular velocity and torque as electrical signals. injecting a first signal for changing any one or more of the angular velocity and the electrical torque of the generator to the rotating shaft included in the generator; (S2) outputting any one or more of the angular velocity and the electrical torque changed by the (S1) step (S3) passing the value output in the step (S2) through a first filter to detect a vibration component by the first signal; and (S4) calculating a torque coefficient using the vibration component detected in the step (S3); and determining the stability of the power system from the calculated torque coefficient.

In addition, the calculating unit (S4) step (S5) passing the detected vibration component through a low pass filter (low pass filter) to change the phase; (S6) the vibration component detected in the step (S3); is the real axis, and the imaginary axis is the vibration component whose phase is changed in step (S5) to obtain the magnitude and phase; (S7) using the magnitude and phase of the vibration component in step (S6) Calculating the torque coefficient; can be performed including.

The calculation unit may determine the stability between the generator and the special equipment in the power system with the calculated torque coefficient, and if the sign of the specifically calculated damping torque coefficient is negative, the stability is determined as an unstable system, and the sign is 0 or positive This can be judged as a stable system. The stability may correspond to an index capable of determining whether it is possible to return to the equilibrium state by attenuating the vibration component included in the electrical torque output by the generator.

The output unit may display a result determined by the determination unit on a display screen for a user to easily understand.

Although the present technology has been described through the above embodiments, the present technology is not limited thereto. The above embodiments may be modified or changed without departing from the spirit and scope of the present technology, and those skilled in the art will recognize that such modifications and changes also belong to the present technology.

Claims (12)

(S1) injecting a first signal for changing any one or more of the angular velocity and the electrical torque of the generator to the rotating shaft included in the generator in the generator model of the power system modeled to output the angular velocity and torque as an electrical signal;
(S2) outputting any one or more of the angular velocity and the electrical torque changed by the step (S1);
(S3) passing the value output in step (S2) through a first filter to detect a vibration component by the first signal; and
(S4) calculating a torque coefficient using the vibration component detected in the step (S3);
A torque coefficient calculation method for determining the stability of the power system with respect to the first signal from the calculated torque coefficient. The method of claim 1,
As a method of determining the stability of the power system
If the sign of the calculated torque coefficient is negative, it is determined that the stability of the power system is unstable, and if it is 0 or a positive number, it is determined that the stability of the torque coefficient is stable. The method of claim 1,
The vibration component is a torque including any one or more of a vibration component generated from an angular deviation of the rotation shaft that is changed by the first signal and a vibration component generated from an electrical torque deviation of the generator that is changed by the first signal Coefficient calculation method. The method of claim 1,
The first filter is a high pass filter (high pass filter) and a band pass filter (band pass filter) is a torque coefficient calculating method. The method of claim 1,
The step (S4) is
(S5) changing the phase by passing the detected vibration component through a low pass filter;
(S6) taking the vibration component detected in step (S3) as a real axis and the vibration component having the phase changed in step (S5) as an imaginary axis to obtain magnitudes and phases;
(S7) calculating a torque coefficient using the magnitude and phase of the vibration component in the step (S6); 6. The method of claim 5,
The torque coefficient in step (S7) includes a damping torque coefficient and a synchronous torque coefficient, and the damping torque coefficient and the synchronous torque coefficient are calculated by the following equation.

(

: electrical torque deviation,

: damping torque coefficient,

: synchronous torque coefficient,

: Angular deviation size

: angular velocity deviation magnitude,

: initial angular velocity,

: Real axis size of vibration component,

: The size of the imaginary contraction of the vibration component,

: changed frequency) As a device for calculating the torque coefficient of the modeled power system,
The device includes an input unit, a calculation unit and an output unit,
the calculation unit
(S1) injecting a first signal for changing any one or more of the angular velocity and the electrical torque of the generator to the rotation shaft included in the generator in the model of the generator on the power system modeled to output the angular velocity and torque as an electrical signal;
(S2) outputting any one or more of the angular velocity and the electrical torque changed by the step (S1);
(S3) passing the value output in step (S2) through a first filter to detect a vibration component by the first signal; and
(S4) calculating a torque coefficient using the vibration component detected in step (S3);
The calculation unit is a torque coefficient calculating device for determining the stability of the power system from the calculated torque coefficient. 8. The method of claim 7,
As a method of determining the stability of the power system
If the sign of the calculated torque coefficient is negative, it is determined that the stability of the power system is unstable, and if it is 0 or a positive number, it is determined that the stability of the power system is stable. 8. The method of claim 7,
The vibration component is a torque including any one or more of a vibration component generated from an angular deviation of the rotation shaft that is changed by the first signal and a vibration component generated from an electrical torque deviation of the generator that is changed by the first signal counting unit. 8. The method of claim 7,
The first filter is a high pass filter (high pass filter) and a band pass filter (band pass filter) is a torque coefficient calculating device. 8. The method of claim 7,
The step (S4) is
(S5) passing the detected vibration component through a low pass filter to change the phase;
(S6) taking the vibration component detected in step (S3) as a real axis and the vibration component having the phase changed in step (S5) as an imaginary axis to obtain magnitudes and phases;
(S7) calculating a torque coefficient using the magnitude and phase of the vibration component in the step (S6); 12. The method of claim 11,
The torque coefficient of step (S7) includes a damping torque coefficient and a synchronous torque coefficient, and the damping torque coefficient and the synchronous torque coefficient are calculated by the following equation.

(

: electrical torque deviation,

: damping torque coefficient,

: synchronous torque coefficient,

: Angular deviation size

: angular velocity deviation magnitude,

: initial angular velocity,

: Real axis size of vibration component,

: The size of the imaginary contraction of the vibration component,

: changed frequency)

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