CN110514902B - Generator excitation shoe insulator resistance detection device - Google Patents
Generator excitation shoe insulator resistance detection device Download PDFInfo
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- CN110514902B CN110514902B CN201910837329.6A CN201910837329A CN110514902B CN 110514902 B CN110514902 B CN 110514902B CN 201910837329 A CN201910837329 A CN 201910837329A CN 110514902 B CN110514902 B CN 110514902B
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R27/00—Arrangements for measuring resistance, reactance, impedance, or electric characteristics derived therefrom
- G01R27/02—Measuring real or complex resistance, reactance, impedance, or other two-pole characteristics derived therefrom, e.g. time constant
- G01R27/025—Measuring very high resistances, e.g. isolation resistances, i.e. megohm-meters
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R27/00—Arrangements for measuring resistance, reactance, impedance, or electric characteristics derived therefrom
- G01R27/02—Measuring real or complex resistance, reactance, impedance, or other two-pole characteristics derived therefrom, e.g. time constant
- G01R27/08—Measuring resistance by measuring both voltage and current
Abstract
The application relates to a generator excitation tile insulator resistance detection device. The device comprises an alternating current power supply, a resistance detection device and a change-over switch device, wherein the alternating current power supply, the change-over switch device and a generator excitation tile insulator are sequentially connected, and the resistance detection device is connected with the alternating current power supply. The resistance detection device is used for detecting the voltage value of the alternating current power supply and the current value on the conducting line and calculating to obtain the insulation resistance value of the generator field shoe insulator on the conducting line. The alternating current power supply is used for generating voltage, the frequency of the voltage is different from the frequency of the rotating speed of the generator, so that the device only senses current with the frequency different from the frequency of the rotating speed of the generator, the interference of shaft voltage on the detection result of the device is eliminated, the accuracy of the detection result is improved, the value of the voltage is smaller than or equal to the value of the shaft voltage of the generator, spark and hydrogen explosion cannot be caused during detection, the test is safe, and the detection reliability is high.
Description
Technical Field
The application relates to the technical field of generator detection equipment, in particular to a generator excitation tile insulator resistance detection device.
Background
During normal operation of the generator, voltage is induced on a rotor large shaft due to the non-concentricity of the stator and the rotor, the residual magnetism of the rotor and the like, and the rotor large shaft is called shaft voltage. To limit the amplitude of the shaft voltage, a grounding brush is usually installed inside the steam side bearing pad base to ground the rotating shaft to approach zero potential. And the excitation end tile bears the shaft voltage, so the shaft bushing, the sealing tile and other parts are arranged to be insulated to the ground, when the insulation is too low, the shaft voltage is grounded through the excitation end tile to form a circulating current, and the damage to the shaft bushing and even the whole generator is caused, so the insulation resistance detection at the excitation tile is very important.
The traditional method for detecting the insulation resistance value at the excitation shoe can be realized by an insulation meter or a multimeter, however, hydrogen in the generator can be slightly gathered at the excitation shoe, and when the insulation value is tested by using the insulation meter, a direct current voltage of hundreds of volts is applied to a component, so that the hydrogen can be exploded due to sparks, and safety accidents can be caused. When the universal meter is used for detection, the output of the universal meter is close to the shaft voltage, so that the reading of the universal meter is interfered, and the reading jumps to cause that the insulation value cannot be correctly displayed. Therefore, the conventional method of detecting the insulation resistance value at the field shoe has low detection reliability.
Disclosure of Invention
In view of this, it is necessary to provide a generator field shoe insulator resistance detection apparatus, which solves the problem of low detection reliability of the conventional method for detecting the insulation resistance value of the field shoe.
A resistance detection device for a generator excitation shoe insulator comprises an alternating current power supply, a resistance detection device and a change-over switch device, wherein the alternating current power supply is connected with the change-over switch device, the change-over switch device is connected with the generator excitation shoe insulator, and the resistance detection device is connected with the alternating current power supply;
the alternating current power supply is used for generating voltage, the frequency of the voltage is different from the frequency of the rotating speed of the generator, the value of the voltage is smaller than or equal to the value of the shaft voltage of the generator, the change-over switch device is used for changing a conducting line of the alternating current power supply and a field shoe insulator of the generator, the resistance detection device is used for detecting the voltage value of the alternating current power supply and the current value of the conducting line, and the insulation resistance value of the field shoe insulator of the generator on the conducting line is obtained through calculation according to the voltage value and the current value.
The resistance detection device of the generator excitation shoe insulator is connected with the generator excitation shoe insulator, the current generated by the alternating current power supply is larger than zero, the change-over switch device is used for changing a conducting circuit with the generator excitation shoe insulator according to actual requirements, the resistance detection device is used for detecting the voltage value of the alternating current power supply and the current value on the circuit after conducting, and calculating according to the voltage value and the current value to obtain the insulation resistance value of the generator excitation shoe insulator on the conducting circuit, the frequency of the voltage generated by the alternating current power supply is different from the rotating speed frequency of the generator, so that the device only induces the current with the frequency different from the rotating speed frequency of the generator, the interference of shaft voltage on the detection result of the device is eliminated, the accuracy of the detection result is improved, the value of the voltage generated by the alternating current power supply is smaller than or equal to the value of the shaft voltage of the generator, and spark and hydrogen explosion cannot be caused during detection, the test is safe, and the detection reliability is high.
Drawings
FIG. 1 is a block diagram of a resistance detection device for an insulator of a field shoe of a generator according to an embodiment;
FIG. 2 is a block diagram of a generator in one embodiment;
FIG. 3 is a block diagram of the resistance detection device of the insulator of the field shoe of the generator in another embodiment;
FIG. 4 is a block diagram of a resistance detection device for the insulator of the field shoe of the generator according to one embodiment;
fig. 5 is a block diagram of a resistance detection device of an insulator of a field shoe of a generator in another embodiment.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described more fully below by way of examples in conjunction with the accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
In one embodiment, referring to fig. 1, a resistance detection device for a field shoe insulator of a generator is provided, the device includes an ac power source 110, a resistance detection device 130, and a switch device 120, the ac power source 110 is connected to the switch device 120, the switch device 120 is connected to a field shoe insulator 210 of the generator, and the resistance detection device 130 is connected to the ac power source 110. The switch device 120 is used for changing a conducting line with the generator field shoe insulator 210, and the resistance detection device 130 is used for detecting a voltage value of the alternating current power supply 110 and a current value on the conducting line, and calculating according to the voltage value and the current value to obtain an insulation resistance value of the generator field shoe insulator 210 on the conducting line. The alternating current power supply 110 is used for generating voltage, the frequency of the voltage is different from the frequency of the rotating speed of the generator, so that the device only senses current with the frequency different from the frequency of the rotating speed of the generator, the interference of shaft voltage on the detection result of the device is eliminated, the accuracy of the detection result is improved, the value of the voltage is smaller than or equal to the value of the shaft voltage of the generator, spark and hydrogen explosion cannot be caused during detection, the test is safe, and the detection reliability is high.
Specifically, in this embodiment, the generator may be a turbine generator, and the turbine generator is a power generation device in which a turbine is used as a prime mover to drive a rotor to rotate, and mechanical energy is converted into electric energy by using the principle of electromagnetic induction. The partial structure of the turbonator is shown in fig. 2, and comprises a high-middle pressure cylinder, a No. 1 low pressure cylinder, a No. 2 low pressure cylinder, a generator, an exciter rotor and an exciter stator which are sequentially arranged, wherein thrust shoes are arranged among the cylinders, the thrust shoes between the generator and the exciter rotor are called as excitation shoes, and the thrust shoes between the generator and the No. 2 low pressure cylinder are called as steam side bearing shoes. During normal operation of the generator, voltage is induced on a rotor large shaft due to the non-concentricity of the stator and the rotor, the residual magnetism of the rotor and the like, and the rotor large shaft is called shaft voltage. In order to limit the amplitude of the shaft voltage, a large shaft at the steam side bearing bush is provided with a shaft grounding carbon brush, so that the large shaft at the steam side bearing bush is close to zero potential, the steam side bearing bush bearing block does not need to be provided with insulation, and only one layer of oil film insulation is arranged between the steam side bearing bush bearing block and the ground. The excitation end tile bears the shaft voltage, so that the bearing bush, the sealing bush and other parts are insulated to the ground, and the shaft voltage is prevented from forming circulation through the grounding of the excitation end tile to damage the bearing bush. However, when the insulation structure at the excitation shoe is damaged and the insulation resistance is too low, the insulation function cannot be achieved, the shaft voltage is grounded through the excitation end shoe to form a circulating current, and the damage to the shaft shoe and even the whole generator is caused, so that the insulation resistance value at the excitation shoe needs to be detected, the fault is prevented and found in time, and the damage to the generator caused by the insulation fault is avoided.
The frequency of the voltage generated by the ac power source 110 is different from the frequency of the generator rotation speed, and the frequency of the voltage generated by the ac power source 110 is not unique as long as the frequency is different from the frequency of the generator rotation speed, and further, the frequency of the voltage generated by the ac power source 110 should be different from the multiple of the frequency of the generator rotation speed, so as to improve the accuracy of the detection result. For example, the rotation speed frequency of a common generator is 25Hz, 50Hz and the like, the multiples of which include 75 Hz, 100Hz and the like, and the frequency of the voltage generated by the alternating current power supply 110 can be 33Hz, so that the generator excitation tile insulator resistance detection device only induces the current with the frequency different from the rotation speed frequency of the generator, the interference of the shaft voltage on the detection result of the device is eliminated, and the accuracy of the detection result is improved. The voltage generated by the ac power supply 110 is not unique, and may be, for example, 2V, the shaft voltage generated by the generator in normal operation is about 3V, and the value of the voltage generated by the ac power supply 110 is less than or equal to the value of the shaft voltage of the generator, so that no spark or hydrogen explosion is caused during detection, the test is safe, and the detection reliability is high. It is understood that in other embodiments, the frequency and voltage value of the voltage generated by the ac power source 110 may be other values, as long as the implementation is considered by those skilled in the art.
The change-over switch device 120 is used for changing a conducting line with the generator field shoe insulator 210, the resistance detection device 130 is used for detecting a voltage value of the alternating current power supply 110 and a current value on the conducting line, and calculating according to the voltage value and the current value to obtain an insulation resistance value of the generator field shoe insulator 210 on the conducting line, when the change-over switch device 120 is connected with different positions of the generator field shoe insulator 210, the conducting lines are different, and the resistance detection device 130 obtains the insulation resistance value of the generator field shoe insulator 210 at different positions according to different detection of the conducting lines. The structure of the switch device 120 is not exclusive, and may be, for example, a relay, the moving contacts of which are respectively connected to different positions of the generator field shoe insulator 210, and the stationary contacts are conducted with the moving contacts connected to different insulator positions according to different states of the relay coil, so as to change the conducting line with the generator field shoe insulator 210. The switch is controlled according to different combinations of the electrified states of the coils, the switching is convenient, and the automatic control of the conducting circuit can be realized. It is understood that in other embodiments, the switch device 120 may be implemented in other structures, as long as the implementation is considered by those skilled in the art. The structure of the resistance detection device 130 is not unique, and may be, for example, a resistance tester, which is simple to operate and various in types, and can meet the requirements of various occasions. It is understood that in other embodiments, the resistance detection device 130 may be other types of devices, as long as the skilled person realizes this.
In one embodiment, referring to fig. 3, the generator field shoe insulator resistance detection apparatus further includes a current limiting device 140, and the ac power source 110 is connected to the switch apparatus 120 through the current limiting device 140. The current limiting device 140 is used to limit the current in the conducting line, so as to prevent the device from being damaged by the excessive current.
Specifically, when the insulation of the field shoe insulator 210 of the generator is damaged or the current output by the ac power supply 110 is too large, a large current exists in the circuit, the current is too large, which may damage components in the circuit and devices connected to the circuit, and the current limiting device 140 is disposed between the ac power supply 110 and the change-over switch device 120, which may reduce the current in the circuit and improve the safety performance of the field shoe insulator resistance detection device of the generator. The type of the current limiting device 140 is not exclusive, and for example, the current limiting device may be a current limiting resistor R, the current limiting resistor R is connected in series with the switching power supply and the change-over switch device 120 to limit the current of the circuit, the current limiting resistor R has a simple structure, and the production and use costs of the generator field shoe insulator resistance detection device may be saved. The current that restricts as required is big or small different, and the resistance of current limiting resistor R is different, and the model is different, and current limiting resistor R resistance specification is abundant, and application scope is wide. In this embodiment, the resistance value of the current limiting resistor R is selected according to the current after current limiting not exceeding 1A, and it can be understood that in other embodiments, other current limiting resistors R with different resistance values may be selected, which is determined according to actual requirements.
In one embodiment, referring to fig. 4, the switch device 120 is a multi-step switch, the generator field shoe insulator 210 includes two or more oil film insulators 211 and two or more bearing insulators 212, and the multi-step switch is connected to the current limiting device 140 and to the common end of the corresponding oil film insulator 211 and the corresponding bearing insulator 212. The multi-gear switch can switch the common ends of the oil film insulator 211 and the bearing insulator 212 to be conducted with the current limiting device 140, so that the subsequent measurement of the resistance values of the common ends of the oil film insulator 211 and the bearing insulator 212 on a conducting line is facilitated.
Specifically, the number of the oil film insulators 211 and the number of the bearing insulators 212 are two or more, and the number of the oil film insulators 211 and the number of the bearing insulators 212 are four as an example, where the oil film insulators 211 include a first sealing oil equivalent insulation, a second sealing oil equivalent insulation, a first lubricating oil equivalent insulation, and a second lubricating oil equivalent insulation, the bearing insulators 212 include an inner oil level insulation, a sealing shoe insulation, a bearing bush insulation, and an outer oil level insulation, the multi-level switch is connected to the current limiting device 140 and connected to a common end of the first sealing oil equivalent insulation and the inner oil level insulation, a common end of the second sealing oil equivalent insulation and the sealing shoe insulation, a common end of the first lubricating oil equivalent insulation and the bearing bush insulation, or a common end of the second lubricating oil equivalent insulation and the outer oil level insulation, so as to measure resistance values of insulators connected to four different common ends, and facilitate positioning of a specific position of an insulation fault, the detection precision of the generator excitation shoe insulator resistance detection device is improved.
In one embodiment, the multi-gear switch comprises two or more than two fixed contacts and movable contacts, the fixed contacts are connected with the current limiting device 140, and each movable contact is respectively connected with the common end of the corresponding oil film insulator 211 and the bearing insulator 212. By changing the conduction of the fixed contact and different movable contacts of the multi-gear switch, the conduction of the common ends of different oil film insulators 211 and bearing insulators 212 and the current limiting device 140 can be switched, so that the subsequent measurement of the resistance values of the common ends of the oil film insulators 211 and the bearing insulators 212 on a conducting line is facilitated.
Specifically, the number of the movable contacts is not unique, each movable contact is connected with the common end of the corresponding oil film insulator 211 and the corresponding bearing insulator 212, the number of the movable contacts can be smaller than, equal to or larger than the number of the common ends of the oil film insulator 211 and the corresponding bearing insulator 212, when the number of the movable contacts is smaller than the number of the common ends of the oil film insulator 211 and the corresponding bearing insulator 212, the movable contacts are connected with the movable contacts by changing different common ends during measurement, and then the movable contacts are conducted with the fixed contacts, so that the purpose of measuring the insulation resistance values of insulators at different positions corresponding to different common ends can be achieved, the number of the movable contacts is small, and the use cost can be saved. When the number of the movable contacts is equal to the number of the common ends of the oil film insulator 211 and the bearing insulator 212, one movable contact is correspondingly connected with the common end of one oil film insulator 211 and the bearing insulator 212, and when the device is used, the insulation resistance values of insulators at different positions corresponding to different common ends can be measured only by changing the conduction of the fixed contact and different movable contacts, no additional wiring is needed, and the device is convenient to use. When the number of the movable contacts is larger than the number of the common ends of the oil film insulator 211 and the bearing insulator 212, the common ends of each oil film insulator 211 and the bearing insulator 212 are respectively connected with different movable contacts, and other movable contacts can have other different functions, so that the generator excitation shoe insulator resistance detection device has more functions and more applicable occasions.
In this embodiment, taking the example that the number of the moving contacts is greater than the number of the common ends of the oil film insulator 211 and the bearing insulator 212, the number of the moving contacts is five, the number of the common ends of the oil film insulator 211 and the bearing insulator 212 is four, the oil film insulator 211 comprises a first sealing oil equivalent insulation, a second sealing oil equivalent insulation, a first lubricating oil equivalent insulation and a second lubricating oil equivalent insulation, the bearing insulator 212 comprises an inner oil level insulation, a seal shoe insulation, a bearing bush insulation and an outer oil level insulation, specifically, the seal shoe insulation comprises a seal shoe transition ring inner insulation and a seal shoe transition ring outer insulation, the bearing bush insulation comprises a bearing bush inner insulation and a bearing bush outer insulation, the common end of the first sealing oil equivalent insulation and the inner oil level insulation, the common end of the seal shoe transition ring inner insulation and the seal shoe transition ring outer insulation, the common end of the bearing bush inner insulation and the bearing bush outer insulation, and the common end of the second lubricating oil equivalent insulation and the outer oil level insulation are respectively connected with four different ends When the static contact is conducted with different movable contacts, the insulation part correspondingly connected with the movable contact can be connected into the generator excitation shoe insulator resistance detection device to measure the insulation resistance values of the different insulation parts, the movable contact also comprises a withdrawing position movable contact, when the static contact is conducted with the withdrawing position, a circuit is disconnected, the generator excitation shoe insulator resistance detection device stops working, the working state of the generator excitation shoe insulator resistance detection device is conveniently and timely stopped when abnormality or other emergency occurs to equipment, the protection device is played, and the operation is convenient. It is understood that in other embodiments, the position of the insulator of the movable contact connection can be other positions to measure the insulation resistance value of other insulation components, as long as the skilled person can realize the measurement.
In one embodiment, referring to fig. 4, the device for detecting the resistance of the field shoe insulator of the generator further includes a controller 150, the multi-stage switch further includes an automatic position contact, the automatic position contact is connected to the controller 150, the controller 150 is further connected to the oil film insulator 211 and the common end of the bearing insulator 212, and when the stationary contact and the automatic position contact are conducted, the controller 150 controls the automatic position contact to be conducted to the common end. When the multi-gear switch comprises an automatic position movable contact, the multi-gear switch and the controller are both connected with the common ends of the oil film insulator 211 and the bearing insulator 212, the multi-gear switch comprises an automatic test mode and a manual test mode, when the multi-gear switch is in the manual control mode, a tester can be conducted with different movable contacts by changing the fixed contact, the insulation resistance values of insulators at different positions corresponding to different common ends can be measured, additional wiring is not needed, and the use is convenient. When the multi-gear switch is in a manual control mode, the controller 150 controls whether the multi-gear switch is conducted with the common end of the oil film insulator 211 and the bearing insulator 212, when the multi-gear switch is conducted, the generator excitation shoe insulator resistance detection device detects the insulation resistance value of the generator excitation shoe insulator 210, and when the multi-gear switch is disconnected, the generator excitation shoe insulator resistance detection device stops working, so that the automation degree of the generator excitation shoe insulator resistance detection device is improved. When the number of the oil film insulators 211 and the number of the bearing insulators 212 are two or more, taking the number of the oil film insulators 211 and the number of the bearing insulators 212 as four as an example, the four common ends are all connected to the controller 150, when the stationary contact of the multi-stage switch is conducted with the automatic position movable contact, the controller 150 controls the automatic position movable contact to be conducted with the common ends according to a preset working condition, the preset working condition is not unique, for example, the preset working condition may be a preset working duration, and the automatic position movable contact is automatically switched to be conducted with the next common end after the automatic position movable contact is conducted with one of the common ends for the preset duration, so as to improve the testing efficiency. The type of the Controller 150 is not exclusive, and for example, the Controller may be a PLC (Programmable Logic Controller), an input/output function module of the PLC is complete, and for different field signals (such as direct current or alternating current, switching value, digital or analog value, voltage or current, etc.), corresponding templates may be directly connected to devices (such as buttons, switches, sensor current transducers, motor starters or control valves, etc.) in the industrial field, and the PLC is easy to program, high in integration level, and convenient to use. It is understood that in other embodiments, the controller 150 may be implemented by other types of devices, as long as the corresponding control functions are implemented.
In one embodiment, the controller 150 is further configured to receive a shaft current signal of the generator, and the controller 150 controls the automatic position contact to conduct with the common terminal when the value of the received shaft current is greater than a preset shaft current threshold. When the value of the shaft current is larger than the preset shaft current threshold value, the generator is considered to be abnormal in work, and at the moment, the controller 150 controls the automatic position moving contact to be conducted with the public end, so that the generator excitation tile insulator resistance detection device can detect the insulation resistance value of the generator excitation tile insulator 210, and an insulation fault can be found in time.
Specifically, during normal operation of the turbonator, direct-current induced electricity can be generated due to friction between steam and blades and between steam and a cylinder, and the high-medium pressure cylinder, the No. 1 low pressure cylinder, the No. 2 low pressure cylinder and the large shaft are all grounded, so that the induced voltage is small in amplitude generally and cannot break through an oil film, and therefore bearing bush bearings arranged on two sides of the high-medium pressure cylinder, the No. 1 low pressure cylinder and the No. 2 low pressure cylinder are not provided with insulation for a bearing box, and only one layer of oil film insulation exists between the large shaft and the ground. A double-winding current transformer is arranged on a large-shaft grounding cable at a steam-side bearing bush to accurately measure grounding current of the whole shaft system, namely shaft current, so as to reflect whether the shaft system has a second grounding point or not to enable shaft voltage or induced current to form circulating current. The double-winding type current transformer is connected with the controller 150, the controller 150 is used for receiving a shaft current signal sent by the double-winding type current transformer, when the value of the received shaft current is larger than a preset shaft current threshold value, the controller 150 considers that the generator works abnormally, at the moment, the controller 150 controls the automatic potential movable contact to be conducted with the public end, and therefore the generator excitation tile insulator resistance detection device can detect the insulation resistance value of the generator excitation tile insulator 210 and find insulation faults in time. The value of the preset shaft current threshold is not unique, and may be, for example, 2A, and when the value of the shaft current received by the controller 150 is greater than 2A, the automatic position moving contact is controlled to be conducted with the common terminal. Or, the preset shaft current threshold may include a current threshold and a time threshold, for example, the current threshold is 0.2A, and the time threshold is 10s, when the value of the received shaft current is greater than 0.2A and the duration is greater than 10s, the controller 150 controls the automatic position movable contact to be conducted with the common end, so that the generator excitation shoe insulator resistance detection device may detect the insulation resistance value of the generator excitation shoe insulator 210, and find the insulation fault in time. It is understood that in other embodiments, the preset shaft current threshold may have other values, as long as the skilled person realizes.
In one embodiment, referring to fig. 4, the resistance detecting device 130 includes a voltmeter 131, an ammeter 132, and a voltage/current processing unit 133, the voltmeter 131 is connected in parallel with the ac power source 110, one end of the ammeter 132 is connected to the ac power source 110, the other end is grounded, both the voltmeter 131 and the ammeter 132 are connected to the voltage/current processing unit 133, and the voltage/current processing unit 133 is configured to calculate the insulation resistance value of the generator field shoe insulator 210 on the conducting line according to the voltage value detected by the voltmeter 131 and the current value detected by the ammeter 132.
Specifically, the voltmeter 131 is used for detecting the voltage on both sides of the ac power source 110, the ammeter 132 is used for detecting the current value on the conducting line, and the voltage and current processing unit 133 is used for calculating the insulation resistance value of the generator field shoe insulator 210 on the conducting line according to the received voltage value and current value. The way in which the voltage-current processing unit 133 calculates the resistance value is not exclusive, and when the received voltage is Ui and the received current is Ii, the voltage-current processing unit 133 obtains the input impedance Zi according to Ui/Ii, and vector calculation is performed on Zi to obtain the insulation resistance value of the generator field shoe insulator 210. When the conducting line further comprises a current limiting resistor R, the voltage and current processing unit 133 calculates the input impedance Zi, and then performs vector operation on Zi and subtracts the resistance value of the current limiting resistor to obtain the insulation resistance value of the generator excitation tile insulator 210, and when the resistance detection device 130 comprises the voltmeter 131, the ammeter 132 and the voltage and current processing unit 133, the insulation resistance value of the generator excitation tile insulator 210 can be obtained through simple calculation, so that the use is convenient. The controller 150 can also store the calculated measured values for subsequent use by the operator in data analysis, fault determination, and the like.
In one embodiment, referring to fig. 4, the generator field shoe insulator resistance detection apparatus further includes a fuse 160, one end of the fuse 160 is connected to the ammeter 132, and the other end is grounded. The fuse 160 is used to open the circuit when the current exceeds a preset value, so as to prevent the device in the circuit from being damaged by a large current.
Specifically, the fuse 160 has one end connected to the ammeter 132 and the other end grounded. When the current transmitted on the conducting line of the generator excitation shoe insulator resistance detection device exceeds a preset value, the fuse 160 fuses the melt by the heat generated by the fuse 160, so that the circuit is disconnected, devices in the circuit and components connected with the circuit are prevented from being damaged by overlarge current, and the overcurrent protection effect is achieved. The preset value is the maximum value of the current allowed to pass through the fuse 160, the types of the fuse 160 are different according to the maximum value of the allowed current, and the corresponding type of the fuse 160 can be selected according to the maximum value of the current in the circuit as long as the function of overcurrent protection can be achieved. The fuse 160 is applied to the resistance detection device of the excitation shoe insulator of the generator, so that the service life of the device can be effectively prolonged, and the fuse 160 is simple in structure and convenient and fast to use.
In one embodiment, referring to the figure, the device for detecting the insulator resistance of the field shoe of the generator further includes a frequency-selecting circuit 170, and the ac power source 110 is connected to the switch device 120 through the frequency-selecting circuit 170. The frequency selection circuit 170 only allows voltage signals with specific frequency to pass through, filters signals with other frequencies, and is beneficial to improving the purity of the signals, so that the working performance of the generator excitation tile insulator resistance detection device is ensured. The reserved frequency of the frequency selecting circuit 170 is determined according to the frequency of the voltage generated by the ac power source 110, for example, when the frequency of the voltage generated by the ac power source 110 is 33Hz, the frequency selecting circuit 170 only allows the voltage signal with the frequency of 33Hz to pass through, so as to eliminate the interference of the axis voltage on the detection device and improve the accuracy of the detection result.
In one embodiment, referring to fig. 4, the frequency selecting circuit 170 includes an inductor L and a capacitor C, and the ac power source 110 is connected to the inductor L, the capacitor C and the switch device 120 in sequence. When the frequency selecting circuit 170 includes the inductor L and the capacitor C, the structure is simple, and the implementation is easy, the impedance of the frequency selecting circuit 170 is related to the input voltage frequency, that is, related to the output voltage frequency of the ac power supply 110, when the output voltage frequency of the ac power supply 110 is equal to the resonant frequency of the frequency selecting circuit 170, the impedance of the frequency selecting circuit 170 is minimum, at this time, the current flowing through the frequency selecting circuit 170 is maximum, this resonant frequency is the signal frequency that the frequency selecting circuit 170 can pass through, and when the voltage frequency generated by the ac power supply 110 is 33Hz, the resonant frequency of the frequency selecting circuit 170 is 33Hz, that is, only the current signal with the frequency of 33Hz is allowed to pass through, so as to reduce the influence of the shaft voltage on the detection result.
In one embodiment, referring to fig. 5, the generator field shoe insulator resistance detection device further includes a display device 180, and the display device 180 is connected to the resistance detection device 130 and is used for displaying the insulation resistance value of the generator field shoe insulator 210 detected by the resistance detection device 130. The insulation resistance value of the generator excitation shoe insulator 210 can be intuitively obtained through the information displayed by the display device 180, so that the insulation state of the generator excitation shoe insulator 210 can be conveniently known in real time.
Specifically, the specific type of the display device 180 is not exclusive, and may be, for example, a display screen, where the display screen may display the resistance value information sent by the resistance detection device 130 in a form of a numerical value or a graph, and a user may visually obtain the information through the display screen. The display device 180 may also be a touch screen, where the touch screen includes a display screen and a touch screen, the display screen is used for displaying information, the touch screen may implement human-computer interaction, a worker may send an instruction through the touch screen, the touch screen sends the received instruction to the resistance detection device 130, and the resistance detection device 130 operates according to the received instruction, for example, when to start and when to stop. The display device 180 can also comprise a prompting lamp, the function of information prompting is mentioned through the color or the flashing state of the prompting lamp, the cost is low, and the use is convenient.
In an embodiment, referring to fig. 5, the resistance detection device for the generator excitation shoe insulator further includes an alarm device 190, the alarm device 190 is connected to the resistance detection device 130, and the resistance detection device 130 sends an alarm signal to the alarm device 190 to alarm when the detected insulation resistance value of the generator excitation shoe insulator 210 is smaller than a preset resistance threshold value, so as to remind a worker to process in time and improve the reliability of the resistance detection device for the generator excitation shoe insulator.
Specifically, the alarm device 190 is not unique in structure, and may include, for example, a warning light and a buzzer, where the warning light may implement the warning function through the color or flashing state of the light, and the buzzer may implement the warning function through the warning sound, so as to remind the operator to handle in time, thereby improving the reliability of the generator field tile insulator resistance detection device. When the insulation resistance value of the generator excitation tile insulator 210 detected by the resistance detection device 130 is smaller than the preset resistance threshold value, the insulation resistance of the generator excitation tile insulator 210 is considered to be too low, the insulation effect is poor, at this time, the resistance detection device 130 sends alarm information to the alarm device 190, the alarm device 190 realizes the alarm function through structures such as a prompting lamp or a buzzer, and the function of warning workers is achieved.
In one embodiment, the resistance detection device of the generator field shoe insulator further comprises a communication device, and the resistance detection device 130 and the controller 150 are both connected with the communication device. The user can send the insulation resistance value detected by the resistance detection device 130 to the terminal device through the communication device, the user can also send an operation instruction to the controller 150 through the communication device, and the controller 150 controls the automatic position movable contact to be conducted with the public end after receiving the operation instruction, so that the remote control of the resistance detection device of the generator excitation tile insulator is realized.
Specifically, the structure of the communication device is not unique, and may include, for example, a WIFI device and/or a bluetooth device, and the communication device may establish a communication connection with the user terminal or the cloud platform, implement data transmission with a corresponding APP on the user terminal, or perform data exchange with the cloud platform. The interface type of the communication device is not unique, for example, the interface type can be a UART, SPI, USB, WIFI, RF or bluetooth interface, etc., and the communication device can be adjusted according to actual requirements and is flexible to use. Taking the APP corresponding to the user terminal as an example, the communication device sends the resistance information sent by the resistance detection device 130 to the user terminal, and the APP on the user terminal records the information of the information, so as to facilitate subsequent analysis processing. The user can also predetermine operating parameter on user terminal, APP sends operating parameter for communication device, after communication device received and analysis processes the information, with operating parameter information transmission to controller 150, by controller 150 control automatic position movable contact with which public end switch on, it is how long what etc. of duration that switches on, realize intelligent detection, the public end scheduling problem that needs manual adjustment to connect in the testing process has been solved, generator excitation tile insulator resistance detection device's use reliability has been improved.
The generator excitation shoe insulator resistance detection device is connected with the generator excitation shoe insulator 210, the current generated by the alternating current power supply 110 is larger than zero, the change-over switch device 120 is used for changing a conducting circuit with the generator excitation shoe insulator 210 according to actual requirements, the resistance detection device 130 is used for detecting the voltage value of the alternating current power supply 110 and the current value on the conducting circuit, and calculating according to the voltage value and the current value to obtain the insulation resistance value of the generator excitation shoe insulator 210 on the conducting circuit, the frequency of the voltage generated by the alternating current power supply 110 is different from the frequency of the rotating speed of the generator, so that the device only induces the current different from the frequency of the rotating speed of the generator, the interference of shaft voltage on the detection result of the device is eliminated, the accuracy of the detection result is improved, the value of the voltage generated by the alternating current power supply 110 is smaller than or equal to the value of the shaft voltage of the generator, and spark and hydrogen explosion cannot be caused during detection, the test is safe, and the detection reliability is high.
The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.
The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.
Claims (11)
1. The resistance detection device for the generator excitation shoe insulator is characterized by comprising an alternating current power supply, a resistance detection device and a change-over switch device, wherein the alternating current power supply is connected with the change-over switch device, the change-over switch device is connected with the generator excitation shoe insulator, and the resistance detection device is connected with the alternating current power supply;
the alternating current power supply is used for generating voltage, the frequency of the voltage is different from the multiple of the frequency of the rotating speed of the generator, the value of the voltage is smaller than or equal to the value of the shaft voltage of the generator, the change-over switch device is used for changing a conducting line with a field shoe insulator of the generator, the resistance detection device is used for detecting the voltage value of the alternating current power supply and the current value on the conducting line, and the insulation resistance value of the field shoe insulator of the generator on the conducting line is obtained through calculation according to the voltage value and the current value; the alternating current power supply is connected with the change-over switch device through the current limiting device.
2. The device of claim 1, wherein the change-over switch device is a multi-gear switch, the generator field shoe insulator comprises an oil film insulator and a bearing insulator, the number of the oil film insulators and the number of the bearing insulators are two or more, and the multi-gear switch is connected with the current limiting device and connected with a common end of the corresponding oil film insulator and the corresponding bearing insulator.
3. The device of claim 2, wherein the multi-step switch comprises two or more than two fixed contacts and two or more than two movable contacts, the fixed contacts are connected with the current limiting device, and each movable contact is respectively connected with the common end of the corresponding oil film insulator and the bearing insulator.
4. The apparatus of claim 3, further comprising a controller, said multi-position switch further comprising an automatic indexing contact, said automatic indexing contact connected to said controller, said controller further connected to a common end of said oil film insulator and said bearing insulator; when the static contact is conducted with the automatic position movable contact, the controller controls the automatic position movable contact to be conducted with the public end.
5. The apparatus of claim 4, wherein the controller is further configured to receive a shaft current signal of the generator, and wherein the controller controls the automatic position contact to conduct with the common terminal when the received shaft current is greater than a predetermined shaft current threshold.
6. The device according to claim 1, wherein the resistance detection device comprises a voltmeter, an ammeter and a voltage and current processing unit, the voltmeter is connected in parallel with the alternating current power supply, one end of the ammeter is connected with the alternating current power supply, the other end of the ammeter is grounded, the voltmeter and the ammeter are both connected with the voltage and current processing unit, and the voltage and current processing unit is used for calculating the insulation resistance value of the field shoe insulator of the generator on the conducting line according to the voltage value detected by the voltmeter and the current value detected by the ammeter.
7. The apparatus of claim 6, further comprising a fuse, one end of the fuse being connected to the ammeter and the other end being connected to ground.
8. The apparatus of claim 1, further comprising a frequency selection circuit, wherein the ac power source is connected to the switch apparatus through the frequency selection circuit.
9. The apparatus of claim 8, wherein the frequency selective circuit comprises an inductor and a capacitor, and the ac power source is connected to the inductor, the capacitor and the switch device in sequence.
10. The device according to any one of claims 8-9, further comprising a display device, wherein the display device is connected to the resistance detection device and is used for displaying the insulation resistance value of the generator field shoe insulator detected by the resistance detection device.
11. The device according to any one of claims 1 to 9, further comprising an alarm device, wherein the alarm device is connected with the resistance detection device, and the resistance detection device sends an alarm signal to the alarm device to alarm when the detected insulation resistance value of the generator excitation tile insulator is smaller than a preset resistance threshold value.
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| CN111983324B (en) * | 2020-07-03 | 2023-06-16 | 中广核核电运营有限公司 | Method and device for measuring resistance of sealing tile of generator by equipotential method |
| CN111983323B (en) * | 2020-07-03 | 2023-09-19 | 中广核核电运营有限公司 | Method and device for measuring resistance of generator sealing tile by induced voltage method |
| CN111983325B (en) * | 2020-07-03 | 2023-04-07 | 中广核核电运营有限公司 | Method and device for measuring resistance value of generator sealing tile by current time method |
| CN117554766B (en) * | 2024-01-09 | 2024-03-26 | 成都瑞讯物联科技有限公司 | Insulation on-line monitoring method and monitoring device |
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