CN205157637U - Generator carbon brush current distribution monitoring system - Google Patents

Abstract

The utility model provides a generator carbon brush current distribution monitoring system, which is mainly used in environments such as large-scale hydroelectric power stations, thermal power stations, and pumped storage power stations. The utility model provides a generator carbon brush current distribution monitoring system, which includes three parts: a DC current sensor, a signal acquisition transmission box and a host computer; the DC current sensor adopts a high-precision current sensor to collect and transform the DC current of each carbon brush After that, it is transmitted to the signal acquisition and transmission box; the signal acquisition and transmission box converts the received current signal into a digital signal after denoising and filtering, and transmits it to the host computer, which performs data processing and judgment; the whole system is powered by 220V. The generator carbon brush current distribution monitoring system can accurately collect the DC current signal in a strong interference environment, and send the data to the remote monitoring terminal through the wireless transmission module. The entire system adopts an integrated design and is placed in a shielded box to ensure the working stability of each component.

Description

Generator Carbon Brush Current Distribution Monitoring System

technical field

The utility model relates to an online detection system for generator carbon brush current, which is mainly used in environments such as large-scale hydropower stations, thermal power stations, and pumped storage power stations. In order to reduce the failure of carbon brushes, improve the overall operating life of carbon brushes, and ensure the safe and stable operation of the generator.

Background technique

At present, my country's power grid construction is developing rapidly, and power plants are an important part of the power system operation, and their safe and stable operation is very important. During the operation of the generator set, the serious wear and excessive temperature of the carbon brushes in the excitation system are common problems in domestic power plants, especially in pumped storage power plants. When the generator carbon brushes run abnormally, the current distributed on each carbon brush will also change, so monitoring the current distribution of each carbon brush is very important for judging carbon brush faults and ensuring the stable operation of the generator excitation system meaning.

The inventor of the utility model found in the actual investigation that in the prior art, technicians usually use clamp-type ammeters, infrared imagers, etc. to detect the operation of carbon brushes from time to time, but these two methods are relatively cumbersome and difficult to implement. Real-time online monitoring of carbon brush operation status.

Utility model content

The technical problem to be solved by the utility model is closely surrounding the main problem of the current carbon brush operation performance detection technology of the generator excitation system, including:

(1) The infrared imager can only monitor the collector rings and carbon brushes of the generator at regular intervals, which requires manual fixed-point operation, and the real-time performance is poor. Moreover, the temperature is a phenomenon of carbon brush heating, and there is a lag in failure.

(2) Personnel observation consumes too much manpower, and it is difficult to judge the carbon brush that is about to fail.

In order to solve the above technical problems, the utility model provides a carbon brush current distributed monitoring system, which mainly includes three technical contents:

(1) DC current sensing technology with strong anti-interference ability and high output current accuracy

(2) Small signal acquisition and transmission technology in complex environment

(3) Man-machine interface interaction and fault pre-judgment technology

The utility model provides a generator carbon brush current distribution monitoring system, which includes three parts: a DC current sensor, a signal acquisition transmission box and a host computer;

The DC current sensor adopts a high-precision current sensor, which collects and transforms the DC current of each carbon brush and transmits it to the signal acquisition and transmission box; the signal acquisition and transmission box converts the received current signal into a digital signal after denoising and filtering and transmits it to the host computer, the upper computer performs data processing and judgment; the whole system is powered by 220V.

The DC current sensor includes a sensing element and a transmission line. The sensing element and the braid of the carbon brush are electrically connected indirectly. The sensing element has strong anti-interference ability and can automatically compensate various factors such as power supply voltage changes, temperature changes, and external magnetic field interference. the impact. The transmission line uses a shielded transmission line to ensure the accuracy of the transmitted signal. After the sensor element collects and transforms the carbon brush current signal, it transmits it to the signal collection transmission box through the transmission line.

The signal acquisition and transmission box includes a signal receiving module, a denoising filter module, a digital-to-analog conversion module and a two-wire transmission module, and the above modules are connected in sequence. The signal receiving module collects and modulates the current signal input by the DC current sensor, and then performs filtering and digital-to-analog conversion through the filter module and the digital-to-analog conversion module. Real-time monitoring is carried out by the host computer in the workshop, and the remote monitoring center stores and organizes the current data as the basis for overall evaluation.

The upper computer in the workshop is used for current change display and system failure prediction. It can display the current signal change curve collected in real time, predict the running state of the carbon brush through the current change trend, and set the current threshold for the normal operation of the carbon brush. When the current exceeds or falls below the current threshold, the system will automatically alarm and prompt the staff to conduct on-site inspection.

The outstanding advantage of the utility model is that it can accurately collect DC current signals in a strong interference environment, and can send the data to a remote monitoring terminal through a wireless transmission module. The entire system adopts an integrated design and is placed in a shielded box to ensure the working stability of each component. Through the monitoring program, the upper computer system can intelligently judge the collected current data, prevent carbon brush failures early, and ensure the safe and reliable operation of the motor excitation system.

Description of drawings

Figure 1 is a frame diagram of the measurement system of the generator carbon brush current distribution monitoring system.

Figure 2 is a schematic diagram of the installation position of the DC current sensor.

Figure 3 is a block diagram of the signal acquisition and transmission box.

Figure 4 is a schematic diagram of the monitoring interface of the host computer.

In the figure: 1 collector ring; 2 carbon brush; 3 sensing element; 4 brush braid; 5 transmission line.

detailed description

Below in conjunction with accompanying drawing and technical scheme, further illustrate the specific embodiment of the utility model.

Figure 1 is the structure diagram of generator carbon brush current distributed monitoring system. The DC current sensor is responsible for linearly transforming the large current signal on each carbon brush to meet the range requirements of the signal acquisition transmission box. After the signal acquisition and transmission box is introduced by the 220V mains, it is powered by a DC stabilized power supply. The signal acquisition and transmission box is responsible for collecting the current signal transmitted by the current sensor, and filtering and denoising the signal, digital-to-analog conversion, and then the transmission module transmits the data to the upper computer in the workshop and the remote monitoring center. Each system can realize the acquisition and measurement of multi-channel current signals, which can meet the measurement needs of each generator set workshop.

Figure 2 is a schematic diagram of the installation position of the DC current sensor. The sensor is fixed to the pigtail part of each carbon brush and is not directly electrically connected to the pigtail. The sensor transmits the sensed current signal to the signal acquisition transmission box through the shielded transmission line.

Figure 3 is a block diagram of the signal acquisition and transmission box. The entire collection and transmission system is powered by 220V city electricity through a DC voltage regulator module. After the current signal enters the signal acquisition and transmission box, the signal acquisition and transmission box first performs denoising and filtering processing on it, and performs digital-to-analog conversion after eliminating external interference, and converts the collected current analog quantity into digital quantity, and a routing network cable is directly connected to the workshop In the monitoring room, the other channel is directly sent to the remote monitoring center by the wireless transmitting module after being converted by the serial port.

Figure 4 is a schematic diagram of the monitoring interface of the host computer. The interface can display the carbon brush current distribution of the generator set, and the current of each carbon brush can be displayed as a real-time current curve. Through the system algorithm, the collected current data is compared and analyzed. When the carbon brush current is too large or too small, the corresponding carbon brush display in the interface will give a flashing alarm; at the same time, according to experience, the possible fault causes are listed for personnel to troubleshoot and repair.

Claims (3)

1. A generator carbon brush current distribution monitoring system is characterized in that the generator carbon brush current distribution monitoring system comprises three parts of a DC current sensor, a signal acquisition transmission box and an upper computer; The DC current is acquired and transformed and then transmitted to the signal acquisition and transmission box; the signal acquisition and transmission box converts the received current signal into a digital signal after denoising and filtering and transmits it to the host computer, which performs data processing and judgment; the whole system is powered by 220V ; The DC current sensor includes a sensing element and a transmission line. The sensing element and the pigtail of the carbon brush are electrically connected indirectly. After the sensing element converts the collected carbon brush current signal, it is transmitted to the signal acquisition transmission box through the transmission line; The signal acquisition and transmission box includes a signal receiving module, a denoising filter module, a digital-to-analog conversion module, and a two-wire transmission module. The analog-to-analog conversion module performs filtering and digital-to-analog conversion, and the final signal is transmitted to the host computer and the remote monitoring center by the network cable and the wireless transmitter respectively. 2. The generator carbon brush current distribution monitoring system according to claim 1, wherein the DC current sensor is a high-precision current sensor. 3. The generator carbon brush current distribution monitoring system according to claim 1 or 2, wherein the transmission line is a shielded transmission line.