#2 DCS Retrofit Electrical Measurement Installation and Commissioning Overview

First, the situation before the transformation of the equipment I plant # 2 unit before the transformation of the electrical measurement meter, including the transformer group, excitation system, power plant, turbine auxiliary equipment motor measurement circuit, are the original pointer instrument. These meters are installed on the BTG platform of each system. The overhaul and maintenance work is heavy and the process is behind. With the rapid development of modern information technology and power industry, this traditional measurement model can no longer meet the requirements of the times. Digital, computerized data acquisition and processing systems have been fully applied in modern generator sets. The application of DCS control technology of Shanghai Xinhua Control Engineering Co., Ltd. in various types of power stations is becoming more and more extensive and more and more mature. The DCS system electrical measurement and reconstruction of #2 unit of our plant has used the company's advanced functions such as AC sampling and digital communication.

Second, the scope of transformation 2.1 generator - transformer electrical measurement circuit, install a new screen, the screen device consists of multi-functional power monitoring instrument and transmitter.

2.2 Generator-transformer group Energy metering circuit, install a new screen, the screen device consists of two electronic power meter, generator rotor and negative sequence current measuring device, generator insulation overheating monitoring device.

2.36KVIIA, IIB electrical measurement loop, installed in the local switchgear digital multifunctional power monitoring instrument.

2.4 UPS, diesel generator, DC system electrical measurement loop, install a new screen, the screen device consists of transmitter.

2.5380V work section, utility section, security section electrical measurement loop.

III. Installation and Commissioning of Equipment 3.1 Installation of Equipment 3.1.1 Transmitter Panel Installation:

Two 3720 ACM digital power monitoring instruments are installed on the screen to monitor generators and high factory changes. The measured names include generator active power, reactive power, three-phase voltage, three-phase current, frequency, power factor, active power, and no power. Power energy; high plant to change active power, three-phase current, active power; four active power transmitters, to provide thermal power generator DEH, MCS generator signal; a rotor and negative sequence current transducer; two frequency changes The sender provides signals to the thermal CCS system.

The 3720ACM meter of generator and Gaochangchang is connected to RTU and #2 DCS through its own two RS485 communication ports. The electrical parameters of the generator and the plant are displayed on the ECS screen. The rotor and negative sequence current transmitter use its own RS485 communication port to communicate with the rotor negative sequence current display device installed on the power meter screen, and use the RS485 port of the display device to communicate with the #2 DCS system.

3.1.2 # 2 transformer group meter installation:

Two electronic watt-hour meters are installed in the screen to measure the power of the alternator and the high factory, and communicate with the DCS system of the #2 machine through the RS485 communication port of the watt-hour meter. The energy data is displayed in the ECS system parameter table. . The equipment installed in the screen is also the generator insulation overheat monitoring device, which uses the front-end detection device to provide a pair of device alarm contact signals to the ECS system.

3.1.3 #2 factory transmitter screen installation:

The screen is used to measure UPS, diesel generator, and DC power system. It is composed of a transmitter. The output 4-20mA analog quantity is sent to the AI ​​quantity acquisition board of ECS#2 cabinet. Real-time data is displayed on the ECS screen.

3.1.4 AC sampling:

With the transformation of the #2 DCS system, Xinhua used some AC card components in the ECS cabinet, which is directly connected to the secondary side of the current transformer and voltage transformer, and converted into digital data through the internal analog/digital conversion of the card. Amount, through the internal software algorithm, displays the primary value of the measured object on the ECS screen. AC sampling has great advantages. It simplifies equipment and intermediate circuits, saves money, and is easier to maintain. The devices and systems for accessing AC sampling cards include: 380V work IIA, IIB bus voltage and standby branch current, 380V security IIA, IIB bus voltage and standby power supply current, 380V lighting II operation and standby power supply current, 380V accident lighting II bus voltage, 380V work section low voltage motor current.

3.1.5380V security section low voltage motor:

This time, the #2 DCS system was reconstructed and all the electronic control equipment in the security section was renewed. The power switch and motor load switch were selected by Schneider Electric and Siemens. The measurement of the motor load directly collects data from a smart module on each switch and sends out an RS485 communication port. All RS485 ports are connected to a communication bus according to the agreed communication connection, and then sent to the engineering station to communicate with the ECS host. The data is displayed directly on the ECS screen.

3.1.66KVIIA, IIB power monitor installation:

A digital power monitor is installed on each interval to collect three-phase voltage and current at each interval. The RS485 communication port on the meter transmits the digital signal to the upper computer. The communication format is Modbus protocol and the active power at each interval can be monitored. , current and other parameters. The 6KVII segment is divided into four communication lines and sent to the upper computer (ECS #7 cabinet) for processing. Then it is sent to the DAS#10 cabinet of the communication station. After being converted by the RS485/RS232 interface, it is sent to the ECS host. The data of each interval is on the ECS screen. display.

3.2 Debugging The device adopts AI quantity transmission mode (4-20mA). The commissioning process of the flow and ECS screen display is basically smooth. The focus of debugging is mainly on the device that uses the communication mode to transmit data. During the commissioning process of generator and transformer measurement, electrical energy, rotor and negative sequence current, and security segment load, due to the different communication protocols and data formats of each device, Xinhua Company encountered some difficulties in software debugging, but it passed the technical staff of Xinhua Company. Efforts have also been successful. The communication debugging time of the 6KV power monitor is relatively long, mainly because of the large number of devices, long communication lines, and many connection points. Through the joint efforts of Xinhua and our team, we have also achieved good results.

The successful debugging of the data communication system shows that Xinhua's products, including hardware and software, have strong compatibility and stability. For different types of equipment, they can meet the requirements of data communications. At the same time, Xinhua's engineers and technicians also have good technical qualities and professionalism. In the face of difficult problems, they can patiently and meticulously solve problems, reflecting the Xinhua company has very good technical strength.

IV. Operation After the #2 machine was turned on, various electrical measurement parameters were tracked and monitored, and the data were displayed correctly. With the data transmitted by the 6KV power monitor, there is a large fluctuation in the current at several intervals. By querying the history data recorded by the engineer station, it is determined that there is a problem with the instrument. After contacting the manufacturer of the production instrument, the internal software of the instrument was upgraded again. After a period of monitoring, it is operating normally. The entire data communication system is stable and the data display is normal.

5. Before and after the transformation, the maintenance of the #2 machine is reduced, the maintenance of the equipment is reduced, the operating parameters are clear, the measurement accuracy is improved, and the management level is improved. After the transformation, all kinds of electrical quantity data are recorded in the historical database. For the abnormal data, the history curve can be consulted, the cause of the failure can be initially analyzed, and the report can also be printed.

Sixth, transformation experience summary 6.16KVII section debugging because of the tight time, and manufacturers with less time, so the debugging method, find the means of failure is not fully understood. In the process of learning and consulting with Xinhua Company's technical staff, we made detailed records. In particular, there are several problems that are closely related to the actual operation process, such as the maintenance of communication ports. We also conducted a good exchange and achieved Good experience.

6.2 Xinhua's AC sampling has a wide range of application prospects. It is recommended to expand the scope of AC sampling and include the electrical quantities of the generator and 6KV plant. And all AC sampling points are composed of a special collection cabinet, which can communicate with the DCS system, and can also communicate with peripheral remote devices and MIS systems. In this way, the equipment can be more streamlined, the functions of its own products can be improved, and maintenance can be made easier.

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