KR100920895B1 - System for monitering shaft voltage and current generator - Google Patents

Abstract

PURPOSE: A system for monitoring a shaft voltage and current of a generator is provided to detect a cause of a problem at a generator accurately by comparing a detected shaft voltage and current of the generator with a parameter set by a user. CONSTITUTION: In a system for monitoring a shaft voltage and current of a generator, a detection unit(130) detects the shaft voltage / current of a generator but the shaft current is detected through a low resistance shunt. An input value of an AD converter and a parameter set by the user which is stored in a memory(151) are compared and analyzed. An analyzed result is converted into various event data required for a monitoring. A user input application(Man Machine Interface: MMI) is expressed as various forms including a graphic, a chart, and a report.

Description

Generator Axial Voltage / Axial Current On-Line Monitoring System {System for Monitering Shaft Voltage and Current Generator}

The present invention relates to a generator axial voltage / axial current on-line monitoring system, and more particularly, the axial voltage / axial current of the generator generated by the induction magnetic field in the generator rotated by the electrostatic induction in the turbine and the rotation of the turbine Is detected on-line in real time through a brush made of Copper Braid, and compared with user-set parameters and monitored in three dimensions by a monitoring server to generate instant discharge. A line monitoring system.

In general, a turbine generator rotates the rotation shaft of the generator rotor through the coupling using the turbine shaft as a rotating means. The coil is applied to the slip ring so that the coil is insulated from each other through the conductor, and the brush connected to the slip ring rectifies AC power so that the DC power is applied. Therefore, the DC power is applied to the coil through the brush and the slip ring. Becomes When the rotor in the electromagnet state rotates, a magnetic field is applied to the stator, and an induction voltage is generated in the winding forming the stator by the magnetic field applied to the stator to output the generated current through the output terminal.

Power is supplied to the coil through the rectifier brush and the slip ring to the rotary shaft, but the spike component is applied to the coil by the turn on / off action of the rectifier elements such as diodes. However, the coil is insulated against current, and the spike component is applied to the bearing connected to the housing to generate the axial current. The axial voltage generated during generator operation is mainly generated by the generator rotor, and the axial current flows to the ground through the generator bearing and the seal ring. At this time, when the other bearing and the closed loop are formed, a circulating current is generated and friction of the bearing is generated. Rubbing and vibration are caused.

Conventional turbine generator axial voltage is divided into a direct current component and an alternating current component. The direct current component mainly depends on the dryness of the turbine steam and is caused by an electrostatic phenomenon between the braid and the diaphragm of the turbine. AC components vary in the shape of axial voltage depending on the imbalance of the magnetic flux distribution of the stator, the vertical gap of the air gap, the asymmetry of the rotor magnetic flux, the leakage magnetic flux of the rotor end coil, the residual magnetic flux, the magnetic saturation, and the voltage phenomenon of the excitation device. appear. In particular, the double insulation method is adopted to suppress the high-frequency spike storage voltage caused by the filtration device. However, the axial voltage of 20 [V] or more is discharged through the oil film of the bearing. It is becoming.

In order to prevent this, a ground brush is installed between the generator and the turbine to suppress an increase in the axial voltage, but there is a problem in that reliability is inferior due to insufficient management. In particular, while the switching element by a diode or a thyristor that applies DC power to magnetize the coil of the rotor is turned on and off periodically, a spike current appears in the rotor, and the counter electromotive force for the change of the current is generated between the rotor coil and the ground. It acts as a capacitor, and since such a capacitor flows well at higher frequencies, this voltage acts on the rotor body, causing an increase in the axial voltage. In addition, if the axis is small, the inductance of the axis is large, and the high frequency spike voltage acts as a large impedance, and thus the high frequency spike component cannot be suppressed. Therefore, the axial voltage acts as a cause of the electrolysis because the insulator of the bearing and the sealing device acts as a capacitor rather than a resistance component against high frequency.

In order to solve this problem, a number of patent technologies have been proposed at home and abroad. In particular, according to Japanese Patent Publication No. 2003-525002 (2003.08.19), which detects and displays the warning of the axial voltage and axial current.

'Receive the output of the voltage sensor 504 for detecting the axial voltage of the rotating electric machine, the current sensor 506 for detecting the current, the voltage module and the signal regulator 508, the active classifier and the signal regulator 510, the signal regulator A channel interface 512, a main bus module 516 receiving the output of the channel interface, a CPU module 518 communicating with the main bus module, an alarm interface 524, a memory module 514, and a display module connected to the CPU module ( A change rate detector for detecting the rate of change of the axial voltage and the axial current detected from the voltage sensor 504 and the current sensor 506, and an evaluation system for alarming as a function of the rate of change of voltage / current and current. A storage voltage and storage current monitoring system is disclosed (claims 1 and 27-43) (see Fig. 1).

However, this technology detects the axial voltage and the axial current of the generator using an unspecified conventional brush, which makes it difficult to detect on-line and real time stably due to the wear of the brush, and is only used for axial voltage grounding. However, the carbon itself wears out during the operation of high voltage rotating equipment, which is expensive due to periodic replacement, and it is dangerous because it requires access to the rotating equipment at high speed.

In addition, if a problem occurs in a rotating machine by automatically evaluating and diagnosing data according to an algorithm in a setupable VCM system, outputting the signal to a signal processing and analysis system having a function selection server (peak voltage / current circuit, average current circuit). Client system with built-in analysis application program and server operation program that converts into event data that can be analyzed according to user setting parameter (algorithm) and correspondingly set by user. Since the system is not built so that it can be analyzed in a variety of patterns, it is difficult to identify the cause of the generator's axial voltage and axial current more accurately and reliably.

In addition, this technology is designed to attach voltage spikes and transient absorbers to the rotating shaft of the generator as needed in addition to monitoring, and there is no discharge function to instantaneously discharge the shaft voltage and shaft current through a monitoring system. Even though it is an expensive monitoring system, there is no linkage to prevent generator voltage and current.

Therefore, the present invention has been made to solve the above problems, the present invention relates to a generator axial voltage / axial current on-line monitoring system, and more particularly to the induction magnetic field in the generator rotated by the rotation of the turbine On-line real-time and stable detection of the axial voltage / axial current of the generator generated by a semi-permanent copper braid brush with a wide contact area to the rotating body and abrasion resistance as a dual sensor, and the detected data and It aims to provide generator regenerative voltage / accumulation current on-line monitoring system that compares and analyzes, converts into event data for analysis, monitors in three dimensions through monitoring server, and instant discharge occurs.

According to a feature of the present invention for achieving the above object,

In a generator axis voltage / axis current on-line monitoring system, in which a rotor rotates by a coupling connecting a turbine and a generator,

In order to monitor the state of the axial voltage / axial current on-line and in real time, the generator uses a special brush made of semi-permanent copper braid with a wide contact area to the rotating body and wear resistance as a dual sensor. A detection unit for detecting an axial voltage / axial current, the axial current being detected through a low resistance sorter (Shunt);

Various events required for monitoring by comparing / analyzing the input value of the A / D converter which converted the axial voltage / axial current signal detected by the detection unit into a digital signal with the user setting parameter stored in the memory (SRAM) A PC-based DAQ unit for converting and controlling data and transmitting the result to a client system through a communication line;

Various event data for monitoring and analysis transmitted from the PC-based DAQ unit, and various types of graphics, charts, reports, etc., for estimating and analyzing the cause of generation of the axial voltage / axial current of the generator corresponding to the various event data. Storage unit for storing displayed Man Machine Interface (MMI) and server operation program, server and supervisory monitor to display and control analyzed data in three-dimensional display, and analysis of axial voltage and axial current value A client system comprising an alarm to warn step by step and a field indicator to receive and monitor the various event information in the field;

And a discharge circuit unit which is switched by an input of the client system to manually discharge or bypass the storage voltage / store current or is automatically switched by a server of the client system to discharge or bypass. Provides on-line monitoring system for storage voltage and storage current.

Preferably, the axial current of the detector is detected by connecting a low resistance classifier (Shunt) between the detector and the PC-based DAQ unit.

Preferably, the user setting parameter (Parameter),

1) If the axial voltage detected by the axial voltage / axial current detection unit exceeds a predetermined voltage value, it is determined that the electrostatic voltage / residual magnetic voltage is high.

2) If the axis current detected by the axis voltage / axis current detection unit is lower than the preset current value, it is determined as a failure signal of the axis current sensor / fault system.

3) If the shaft voltage is lower than the preset voltage value and the shaft current is higher than the preset current value, it is judged as a bad bearing insulation or a signal in which the shaft and bearing are rubbing.

4) If the shaft voltage is a high signal exceeding the preset voltage value and the shaft current is a high signal exceeding the preset current value, it is determined that the signal is abnormal in the winding of the generator or the core.

5) If the rising rate of the storage voltage is a high signal of 70% or more, it is determined as a contact failure signal of the storage voltage detection sensor.

6) If the threshold value of the shaft voltage is a high signal exceeding the preset voltage value and reaches the highest value, and the threshold value of the shaft current is a high signal exceeding the preset current value and reaches the highest value, the generator exciter It is judged by an abnormality or a bearing seal arcing occurrence signal.

7) If the axial voltage is a high signal exceeding the predetermined voltage value, and the axial current is a high signal exceeding the predetermined current value, it is determined that the signal is abnormal in the winding of the generator or the core.

Preferably, the event data may include a brush failure and a brush contact failure, a ground failure, a bearing insulation failure, a shaft and a bearing friction, a winding and a core failure, an exciter failure, generated in a generator and a turbine according to a signal of the detector. It is characterized by a failure cause such as occurrence of electrostatic voltage by bearing seal arcing and wet steam.

Preferably, the discharge circuit unit is an R-C parallel circuit, characterized in that the current charged in the capacitor (C1) is instantaneously discharged or bypassed along the resistor (R2) as the time constant (τ) elapses.

According to the generator storage voltage / storage current on-line monitoring system of the present invention, the following effects.

1) By using a special brush made of copper braid that can be used semi-permanently, which has a large contact area to the shaft and almost no abrasion, as a dual sensor, On-line monitoring is possible in real time.

2) By detecting and comparing the detected axial voltage / axial current value with the user setting parameter and displaying it on the server and the monitoring monitor in three dimensions, it is possible to identify the cause of failure of the generator more accurately.

3) And the generator axial voltage / axial current prevention system of the present invention has a unique effect of instantaneous discharge of the axial voltage / axial current of the generator manually or automatically through the R-C discharge circuit.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. First, in adding reference numerals to the components of each drawing, it should be noted that the same reference numerals are assigned to the same components as much as possible even though they are shown in different drawings. The prior art should be interpreted as such. In addition, in describing the present invention, when it is determined that the detailed description of the related well-known configuration or function may obscure the gist of the present invention, the detailed description thereof will be omitted.

1 is a schematic view showing a monitoring system of the storage voltage / axial current of the prior art, Figure 2 is a schematic view showing a generator storage voltage / storage current on-line monitoring system according to a preferred embodiment of the present invention, Figure 3 Is a block diagram specifically illustrating a generator shaft voltage / axis current on-line monitoring system according to a preferred embodiment of the present invention, and FIG. 4 is a diagram of a generator shaft voltage / axis current on-line monitoring system according to a preferred embodiment of the present invention. 6 is a circuit diagram illustrating a storage voltage / store current detection unit and a discharge circuit unit. FIG. 5 is a flowchart illustrating a storage voltage / store current estimation method of a generator storage voltage / store current on-line monitoring system according to a preferred embodiment of the present invention. User setting parameters of the generator axial voltage / axial current on-line monitoring system according to a preferred embodiment of the present invention are respectively shown.

Hereinafter, a generator shaft voltage / axis current on-line monitoring system according to a preferred embodiment of the present invention will be described in detail with reference to FIGS. 2 to 6.

Core technical configuration for implementing the generator axial voltage / axial current on-line monitoring system of the present invention is the detection unit 130, PC-based DAQ unit 150, client system 160, communication line 170 and the discharge circuit unit ( 190).

First, referring to FIGS. 2 to 4, the detection unit 130 may include a voltage sensing brush 131 and a grounding brush on the surface of the generator shaft 111. 132 are each configured in duplicate and detect signals capable of monitoring the storage voltage and storage current.

Here, the brush used in the detection unit 130 is a copper plate made by weaving a copper copper wire in a band shape in order to monitor the status of the axial voltage / axial current continuously in real time on-line. Use a special brush made of Copper Braid. This is not only a larger area of contact with the surface of the rotor than the carbon brush, but also rarely damages the bearing or coupling due to an increase in the axial voltage due to poor grounding due to poor contact. In addition, the copper braiding brush has almost no abrasion and can be used semi-permanently, and can be replaced during maintenance of the rotating machine, and thus has a structural feature without problems in stability. On the other hand, the carbon brush is used only for the grounding of the axial voltage, and the carbon itself wears out during the operation of the high voltage rotary machine, and thus should be replaced periodically. And because replacement requires access to a device that rotates at high speed, it is not only dangerous but also expensive to replace.

In addition, in order to measure current between the axial current detection sensor 132 and the PC-based DAQ unit 150, a low-resistance shunt 133 is connected between circuits and a voltage generated at both ends of the low-resistance. Measure the current value by measuring

Referring to FIG. 3, the PC-based DAQ unit 150 is a data acquisition system (DAQ) based on a PC, and the signals detected by the detector 130 are signal processing devices. Acquired from the PC-based DAQ unit 150, the PC-based DAQ unit is converted into various event data for monitoring and analysis by an algorithm and transmitted to the upper server (Sever) through the communication line 170.

In other words, a user setting parameter stored in the memory (SRAM) 151 is an input value of the A / D converter 140 that converts the signal of the axial voltage / axial current detected by the detector 130 into a digital signal. Compared to (), 380, and determined, the control is converted to various event data necessary for monitoring, and the result is transmitted to the server 163 of the client system 160 through the communication line 170.

In addition, the PC-based DAQ unit 150 can synchronize between memory (SRAM) 151 cards through a SSI (System Synchronization Interface) bus, and provides a software designed to perform calibration, and is very easy to calibrate. In the present invention, the user setting parameters are stored as the above-described desirable features so that the axial voltage / axial current signal can be converted into various event data for monitoring and analysis. Alarm thresholds are further stored for alarming step by step upon detection of a fault.

The client system 160 is a computer system that connects with a server system to request a main job or information from a server, and receives a result thereof. In the server 163 of the client system 160 of the present invention, By building a program that can display various event data received from the PC-based DAQ unit 150 in various forms of graphics, the field user can easily monitor and analyze, and if necessary, the field indicator ( System can be configured to monitor and analyze in the field by local indicator or remote place other than server.

In other words, in order to estimate and analyze the various event data for monitoring and analysis transmitted from the PC-based DAQ unit 150 and the cause of generation of the axial voltage / axial current of the generator corresponding to the various event data. And a storage unit 162 for storing a user input application program (MMI) and a server operating program displayed in various forms such as a report, and a server 163 for three-dimensional display and control of the analyzed data on a monitor. And a monitoring monitor 164, an alarm 165 for warning step by step according to whether the axial voltage / axial current value is analyzed, and a local indicator 166 for receiving and monitoring the various event information in the field.

Although not shown in the figure, the server 163 further includes an analysis control unit for analyzing a voltage / current detection value, a voltage / current rising rate, a voltage / current peak value, and a voltage / current DC value.

In addition, the various event data, the brush failure and brush contact failure, ground system failure, bearing insulation failure, shaft and bearing friction, winding and core failure, exciter generated in the generator and turbine according to the signal of the detection unit 130 The above is considered to be the cause of failure such as occurrence of electrostatic voltage caused by bearing seal arcing and wet steam. User setting parameters are input in advance so as to determine the cause of such a failure (see FIG. 6).

The communication line 170 may transmit the data converted by the PC-based DAQ unit 150 to the server 163 through RS-422 (Recommended Standard-422) and TCP / IP (Transmission Control Protocol / Internet Protocol) communication methods. And the field indicator 166.

Referring to FIG. 4, the discharge circuit unit 190 is an RC parallel circuit and means for instantaneously discharging or bypassing the current charged in the capacitor C1 along the resistor R2 as the time constant τ elapses. The relay 180 is switched by the input unit 161 of the client system 160 to manually discharge or bypass the storage voltage / current, or automatically by the server 163 of the client system 160. Switch to discharge or bypass.

Referring to Figures 3 to 5, the overall operating function of the generator axial voltage / axial current on-line monitoring system according to a preferred embodiment of the present invention,

Generator axial voltage / axial current on-line monitoring system of the present invention, by detecting the axial voltage and axial current signal of the generator to monitor the occurrence status of the axial voltage and the health of the ground system to prevent damage to the generator bearing. .

The specific operation of the system is to install the double-sided voltage detection sensor 131 and the axial current detection sensor 132 by a special brush made of copper braid on the surface of the generator shaft 111, respectively. Detects a signal capable of monitoring axial voltage / axial current, and the signals detected from the sensors 131 and 132 are acquired by the PC-based DAQ unit 150, which is a respective signal processing device, and the user of the PC-based DAQ unit. It is converted into various event data for monitoring and analysis by the algorithm which is the setting parameter 380 and transmitted to the upper server 163 through the communication line 170.

In addition, the server 163 may display an MMI (Man Machine Interface) program capable of displaying various types of graphics, charts, and reports corresponding to various event data received from the PC-based DAQ unit. By installing in the storage unit 162, it is configured to be easily monitored and analyzed by the field user, and if necessary, the system can be monitored or analyzed from a remote place other than the server or the field monitoring by the field indicator 166. Can be configured. In addition, the user input unit 161 and the server 163 has a feature that has a discharge circuit section 190 that can instantaneously discharge or bypass the generator axial voltage / axial current.

The above description is merely illustrative of the technical idea of the present invention, and those skilled in the art to which the present invention pertains may make various modifications and changes without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed in the present invention are not intended to limit the technical idea of the present invention but to describe the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments. The scope of protection of the present invention should be interpreted by the following claims, and all technical ideas within the scope equivalent thereto should be construed as being included in the scope of the present invention.

1 is a schematic view showing a storage voltage / storage current monitoring system of the prior art

2 is a schematic view of a generator shaft voltage / shaft current on-line monitoring system according to a preferred embodiment of the present invention;

3 is a block diagram specifically illustrating a generator shaft voltage / axis current on-line monitoring system according to a preferred embodiment of the present invention.

4 is a circuit diagram showing a storage voltage / storage current detection unit and the discharge circuit of the generator storage voltage / storage current on-line monitoring system according to a preferred embodiment of the present invention

5 is a flowchart illustrating a method of estimating an accumulator voltage / axis current of a generator axis voltage / axis current on-line monitoring system according to a preferred embodiment of the present invention.

Figure 6 is a user setting parameter of the generator axis voltage / axis current on-line monitoring system according to a preferred embodiment of the present invention

<Description of the symbols for the main parts of the drawings>

110: generator 111: shaft

120: turbine unit 130: detector

131: axis voltage detection sensor 132: axis current detection sensor

133: shunt 140: A / D converter

150: PC-based DAQ unit 151: memory (SRAM)

160: client system 161: input unit

162: storage unit 163: server

164: surveillance monitor 165: alarm

166: field indicator 170: communication line

180: relay (S / W) 190: discharge circuit

Claims (5)

In a generator axis voltage / axis current on-line monitoring system, in which a rotor rotates by a coupling connecting a turbine and a generator, In order to monitor the state of the axial voltage / axial current on-line and in real time, the generator uses a special brush made of semi-permanent copper braid with a wide contact area to the rotating body and wear resistance as a dual sensor. A detection unit for detecting an axial voltage / axial current, the axial current being detected through a low resistance sorter (Shunt); Various events required for monitoring by comparing / analyzing the input value of the A / D converter which converted the axial voltage / axial current signal detected by the detection unit into a digital signal with the user setting parameter stored in the memory (SRAM) A PC-based DAQ unit for converting and controlling data and transmitting the result to a client system through a communication line; Various types of event data for monitoring and analysis transmitted from the PC-based DAQ unit, and various forms such as graphics, charts, and reports for estimating and analyzing the cause of generation of axial voltage / axial current of a generator corresponding to the various event data. A storage unit for storing user input application program (MMI) and server operation program, server and supervisory monitor for displaying and analyzing analyzed data in three-dimensional display, and A client system comprising an alarm for warning in stages according to analysis and a field indicator for receiving and monitoring the various event information in the field; And a discharge circuit unit which is switched by an input of the client system to manually discharge or bypass the storage voltage / store current or is automatically switched by a server of the client system to discharge or bypass. Capacitance / Capacity On-Line Monitoring System delete The method of claim 1, wherein the user setting parameter (Parameter), 1) If the axial voltage detected by the axial voltage / axial current detection unit exceeds a predetermined voltage value, it is determined that the electrostatic voltage / residual magnetic voltage is high. 2) If the axis current detected by the axis voltage / axis current detection unit is lower than the preset current value, it is determined as a failure signal of the axis current sensor / fault system. 3) If the shaft voltage is lower than the preset voltage value and the shaft current is higher than the preset current value, it is judged as a bad bearing insulation or a signal in which the shaft and bearing are rubbing. 4) If the shaft voltage is a high signal exceeding the preset voltage value and the shaft current is a high signal exceeding the preset current value, it is determined that the signal is abnormal in the winding of the generator or the core. 5) If the rising rate of the storage voltage is a high signal of 70% or more, it is determined as a contact failure signal of the storage voltage detection sensor. 6) If the threshold value of the shaft voltage is a high signal exceeding the preset voltage value and reaches the highest value, and the threshold value of the shaft current is a high signal exceeding the preset current value and reaches the highest value, the generator exciter It is judged by an abnormality or a bearing seal arcing occurrence signal. 7) If the shaft voltage is a high signal exceeding the predetermined voltage value, and the shaft current is a high signal exceeding the predetermined current value, the generator storage voltage, characterized in that it is determined that the signal is abnormal in the winding of the generator or the core. / Axis current on-line monitoring system According to claim 3, The event data is a brush failure and brush contact failure, ground system failure, bearing insulation failure, shaft and bearing friction, winding and core failure, exciter that occurs in the generator and turbine according to the signal of the detection unit The generator axial voltage / axial current on-line monitoring system, characterized in that the cause of the failure, such as the occurrence of the electrostatic voltage caused by the bearing seal arcing and wet steam The generator storage voltage according to claim 4, wherein the discharge circuit unit is an RC parallel circuit, and the current charged in the capacitor C1 is instantaneously discharged or bypassed along the resistor R2 as time constant τ elapses. / Axis current on-line monitoring system

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