Transmission shaft control method of auxiliary relay protection constant value checking device

Abstract

The invention relates to a transmission shaft control method for an auxiliary relay protection constant value checking device. The transmission shaft control method comprises the following steps: installing a transmission shaft motor power acquisition device in the auxiliary relay protection constant value checking device; obtaining given parameters of a motor transmission shaft; according to the motor power transmission model, structure diagram simplification is carried out, a motor power transfer function in relay protection device printing constant value paper feeding is obtained, the motor power transfer function is converted to a time domain, and a time domain analysis model is obtained; calculating the mechanical defect of the disconnecting switch of the combined electric appliance according to the time domain analysis model, judging and calculating the theoretical maximum change rate of the motor power, and judging whether the mechanical defect of the transmission shaft of the motor exists or not by taking the theoretical maximum change rate as a motor power abnormity criterion basis; according to the method, whether the auxiliary relay protection constant value checking device has mechanical defects or not can be monitored on line on the basis of known motor key parameters of the auxiliary relay protection constant value checking device.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of power grid equipment control, and particularly relates to a transmission shaft control method of an auxiliary relay protection setting value checking device. BACKGROUND

[0002] The relay protection device is a vital safety line of the power system in China, and its role is to quickly and accurately cut off the fault point after a fault, prevent the fault from expanding, and ensure the safe and stable operation of the power system. The relay protection setting value, as an important parameter in the relay protection device, plays the role of "fault criterion" in the power system, and its accuracy directly affects the reliability of the relay protection action. Accurate protection setting value can help the protection device make correct judgments and quickly cut off the fault point after a fault; however, incorrect protection setting value will cause the protection device to malfunction and misoperate, expanding the power outage range.

[0003] The relay protection setting value checking work is a regular work in the company, and before the protection device is put into operation, the setting value needs to be set according to the relay protection setting value sheet of the provincial dispatching center, and then the relay protection setting value is printed and checked by the maintenance personnel and the operation personnel. At present, the relay protection setting value checking work of the company is carried out in a manual checking manner, that is, the setting value printed by the relay protection device is compared with each value and unit of the relay protection setting value sheet of the provincial dispatching center. Such checking method highly depends on the concentration of the maintenance personnel and the operation personnel, and has long-term safety hazards. Therefore, it is an urgent need to develop an auxiliary relay protection setting value checking device and a transmission shaft control method of the auxiliary relay protection setting value checking device to improve the reliability of power grid operation. SUMMARY

[0004] The application aims to solve the above problems, and provides a transmission shaft control method of an auxiliary relay protection setting value checking device, which is used for online monitoring of the transmission shaft of the auxiliary relay protection setting value checking device, timely making mechanical defect early warning, and improving the reliability and safety of equipment operation.

[0005] The technical scheme adopted by the application is as follows: a transmission shaft control method of an auxiliary relay protection setting value checking device, which is mainly used for cutting off the control power supply when the transmission shaft of the device is stuck due to failure, and realizing effective protection of the device, and includes the following steps:

[0006] S1: installing a transmission shaft motor power acquisition device in the auxiliary relay protection setting value checking device;

[0007] S2: acquiring given parameters of the motor transmission shaft;

[0008] S3: structure graph simplification is performed according to the motor power transmission model, a motor power transmission function in the printing fixed value of the relay protection device is obtained, the motor power transmission function is transformed to a time domain, and a time domain analytical model is obtained;

[0009] S4: a theoretical maximum change rate of the motor power is calculated according to the time domain analytical model, the theoretical maximum change rate is used as a motor power abnormality criterion basis, and whether there is a mechanical defect of the motor transmission shaft is judged.

[0010] In the step S1, the transmission shaft motor power acquisition device measures the motor power in real time, and obtains a real-time motor power curve P k (t) in the printing fixed value of the relay protection device.

[0011] In the step S2, the motor transmission shaft given parameters are customized according to actual work requirements and provided by the motor transmission shaft manufacturer.

[0012] The motor transmission shaft given parameters include a gain coefficient K q , a damping coefficient ξ, a motor inertia H, an adjustment coefficient R, a time constant T1, and a fault force P e .

[0013] In the step S3, the motor power transmission function is inversely transformed by Laplace to obtain a time domain analytical model of the motor power in the transmission shaft rotation process. The motor transmission shaft gain coefficient K q , the damping coefficient ξ, the motor inertia H, the adjustment coefficient R, the time constant T1, and the fault force P e are all provided by the equipment factory.

[0014] The structure graph is simplified by the motor power transmission model, and an s-domain expression of the motor power is obtained as formula (1)

[0015]

[0016] In the formula, P S is the motor power, R is the adjustment coefficient, K q is the motor mechanical gain coefficient, D is the mechanical damping, the value of which is generally 1, P e is the fault force, ω n is the natural angular frequency, and ξ is the damping coefficient of the motor.

[0017] The natural angular frequency ω n and the expression of the damping coefficient ξ of the motor are calculated as formula (2)-(3).

[0018]

[0019] In the formula, FH is the mechanical work ratio.

[0020] The formula (1) is converted to time domain to obtain a combined electric appliance isolating switch motor power time domain analytical model in the opening and closing process as shown in formula (4):

[0021]

[0022] Wherein, ω r , α is an intermediate calculation variable, and its expression is shown as formula (5)-(7):

[0023]

[0024] In the step 4, the theoretical maximum change rate P Sdmax of the motor power is calculated according to the time domain analytical model for judging the mechanical defect of the combined electric appliance isolating switch.

[0025]

[0026] The motor power needs to meet: the change rate P Sd of the actual measured motor power (t)≤1.2P Sdmax .

[0027] The method of the present application can monitor whether the auxiliary relay protection setting value checking device has mechanical defects on-line according to the motor power in the measuring process on the basis of the known key parameters of the auxiliary relay protection setting value checking device motor. BRIEF DESCRIPTION OF DRAWINGS

[0028] Fig. 1 is a motor power diagram of the auxiliary relay protection setting value checking device under normal conditions;

[0029] Fig. 2 is a motor power diagram of the auxiliary relay protection setting value checking device under abnormal conditions. DETAILED DESCRIPTION

[0030] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. All other embodiments obtained by those skilled in the art without creative labor on the basis of the embodiments in the present application all belong to the scope of protection of the present application, and the following will be specifically described with reference to the embodiments.

[0031] As Figs. 1-2 shown, the present application comprises the following steps:

[0032] S1: installing a transmission shaft motor power acquisition device in the auxiliary relay protection setting value checking device; the specific process is as follows:

[0033] In the step S1, the motor power is measured in real time by the power collection device of the transmission shaft motor, and the real-time motor power curve P in the printing setting value of the relay protection device is obtained. k (t).

[0034] S2: Obtain the given parameters of the motor transmission shaft; the specific process is as follows:

[0035] In the step S2, the given parameters of the motor transmission shaft are customized according to actual work requirements and provided by the motor transmission shaft manufacturer.

[0036] The given parameters of the motor transmission shaft include the gain coefficient K q , the damping coefficient ξ, the motor inertia H, the adjustment coefficient R, the time constant T1, and the fault force P e .

[0037] S3: Simplify the structural diagram according to the motor power transmission model to obtain the motor power transfer function in the printing setting value of the relay protection device, transform the motor power transfer function to the time domain, and obtain the time domain analytical model; the specific process is as follows:

[0038] In the step S3, the motor power time domain analytical model in the transmission shaft rotation process is obtained by inverse Laplace transform of the motor power transfer function. The gain coefficient K q , the damping coefficient ξ, the motor inertia H, the adjustment coefficient R, the time constant T1, and the fault force P e are all provided by the factory.

[0039] The s-domain expression of the motor power is obtained by simplifying the structural diagram of the motor power transmission model as shown in formula (1)

[0040]

[0041] Wherein, P S is the motor power, R is the adjustment coefficient, K q is the motor mechanical gain coefficient, D is the mechanical damping, the value of which is generally 1, P e is the fault force. ω n is the natural angular frequency, and ξ is the damping coefficient of the motor.

[0042] The expressions of the natural angular frequency ω n and the damping coefficient ξ of the motor are calculated as shown in formula (2)-(3):

[0043]

[0044] Wherein, F H is the mechanical work proportion.

[0045] The formula (1) is converted to time domain to obtain a combined electric appliance disconnector motor power time domain analytical model in a closing and opening process as shown in formula (4):

[0046]

[0047] Wherein, ω r , α is an intermediate calculation variable, and its expression is shown in formula (5)-(7):

[0048]

[0049] S4: calculating a theoretical maximum change rate of motor power according to the time domain analytical model for combined electric appliance disconnector mechanical defect judgment, using the theoretical maximum change rate as a motor power abnormality criterion basis to judge whether there is a mechanical defect of a motor transmission shaft. The specific process is as follows:

[0050] In the step 4, the theoretical maximum change rate P Sdmax is calculated according to the time domain analytical model for combined electric appliance disconnector mechanical defect judgment.

[0051]

[0052] The motor power needs to meet: the change rate P Sd (t) of the actual measured motor power is less than or equal to 1.2P Sdmax .

[0053] Specific example analysis:

[0054] The method is described by a motor of an auxiliary relay protection setting value checking device in an experimental environment. The key parameters of the motor are as follows:

[0055] Parameters R H K m ]]> [T1] D P e ]]> Values 1.5 3 0.98 3 1 -95

[0056] The experimental design is divided into two parts. First, the motor power of the auxiliary relay protection setting value checking device meets the normal criterion under normal conditions. The normal actual power curve of the motor of the auxiliary relay protection setting value checking device is as shown in Fig. 1 The parameter of the motor is brought into formula (8) to obtain 1.2P Sdmax is 35.8W / s, and the maximum value of the change rate of the actual power curve in the first time period is 13W / s, which meets the requirement.

[0057] Second, the motor power of the auxiliary relay protection setting value checking device does not meet the normal criterion under abnormal conditions. The abnormal power curve of the motor of the auxiliary relay protection setting value checking device is as shown in Fig. 2The parameters of the motor are brought into equation (8) to obtain 1.2P Sdmax The actual power curve is 35.8W / s, but the rate of change is maximum at 58W / s in the second time period due to the mechanical defect, so it can be judged that the mechanical defect exists, and the power is cut off to perform the emergency stop control.

[0058] It is found through comparison that the method can accurately identify the defect of the transmission shaft of the auxiliary relay protection setting value checking device.

[0059] It is apparent to those skilled in the art that the application is not limited to the details of the foregoing exemplary embodiments, but can be implemented in other concrete forms without departing from the spirit or essential characteristics of the application. Therefore, the embodiments should be considered in all respects as illustrative and not restrictive, the scope of the application being defined by the appended claims rather than the foregoing description, and it is intended that all changes falling within the meaning and range of equivalency of the claims be embraced therein. Any reference signs in the claims should not be construed as limiting the claims to the figures in which the reference signs are used.

Claims

1. A method for controlling the drive shaft of an auxiliary relay protection setting verification device, characterized in that, Includes the following steps: S1: Install a drive shaft motor power acquisition device inside the auxiliary relay protection setting verification device; S2: Obtain the given parameters for the motor drive shaft; S3: Simplify the structural diagram based on the motor power transmission model to obtain the motor power transfer function in the printing setpoint paper feed of the relay protection device. Transform the motor power transfer function to the time domain to obtain the time domain analytical model. S4: Calculate the theoretical maximum rate of change of motor power based on the time-domain analytical model for mechanical defect determination of the combined electrical disconnect switch, and use the theoretical maximum rate of change as the basis for judging abnormal motor power to determine whether there is a mechanical defect in the motor drive shaft.

2. The method for controlling the drive shaft of an auxiliary relay protection setting verification device according to claim 1, characterized in that: In step S1, the drive shaft motor power acquisition device measures the motor power in real time and obtains the real-time motor power curve P in the paper feed of the relay protection device printing the set value. k (t).

3. The method for controlling the drive shaft of an auxiliary relay protection setting verification device according to claim 1, characterized in that: In step S2, the parameters of the motor drive shaft are customized according to actual working requirements and are provided by the motor drive shaft manufacturer.

4. The method for controlling the drive shaft of an auxiliary relay protection setting verification device according to claim 3, characterized in that: The given parameters for the motor drive shaft include the gain coefficient K. q Damping coefficient ξ, motor inertia H, adjustment coefficient R, time constant T1, fault force P e .

5. The method for controlling the drive shaft of an auxiliary relay protection setting verification device according to claim 1, characterized in that: In step S3, the time-domain analytical model of the motor power during the rotation of the transmission shaft is obtained by performing an inverse Laplace transform on the motor power transfer function.

6. The method for controlling the drive shaft of an auxiliary relay protection setting verification device according to claim 5, characterized in that: By simplifying the structural diagram using the motor power transmission model, the s-domain expression for the motor power is obtained: Among them, P S R is the motor power, and K is the adjustment coefficient. q P is the mechanical gain coefficient of the motor, D is the mechanical damping, and its value is generally 1. e The work done by the fault force. ω n Let ξ be the natural angular frequency, and ξ be the damping coefficient of the motor.

7. The method for controlling the drive shaft of an auxiliary relay protection setting verification device according to claim 6, characterized in that: Transforming the s-domain expression of the motor power to the time domain yields the time-domain analytical model of the motor power of the combined electrical disconnector during the opening and closing process, as shown in the following equation: Where, ω r , α is an intermediate calculation variable.

8. The method for controlling the drive shaft of an auxiliary relay protection setting verification device according to claim 1, characterized in that: In step S4, the theoretical maximum rate of change P of the motor power is calculated based on the mechanical defect determination of the combined electrical disconnect switch according to the time-domain analytical model. Sdmax The following equation is obtained by differentiating the s-domain expression of the motor power with respect to time and finding its extrema: Among them, the motor power must meet the following requirement: the rate of change P of the actual measured motor power. Sd (t)≤1.2P Sdmax .

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