With the development of the electric power industry, more and more electric units are used. The timely and accurate verification of the electric energy meter running on the site is a necessary means to ensure electric power safety and accurate electric energy measurement. In the past, the school staff first arranged the calibration task for the day. Then, with the calibrator to the calibration table, the verification result was recorded on the book, and then the verification result was input into the computer. This not only makes the school staff tired of arranging various plans, recording various data, counting various reports, and errors can occur at any time.
Based on the above reasons, an intelligent system for on-site calibration and management of electric energy meter is designed. The solution is based on PDA (Personal Digital Assistant) and GPRS (General Packet Radio Service) technology. It uses PDA to temporarily store data and wirelessly transmit through GPRS network to establish a data communication link between the calibration site and the primary server. Thus, the paperless, automated and intelligent on-site power calibration is realized. At the same time, the system contains a powerful management software to manage the school table data information, in order to achieve the rationalization and systemization of the school work.
This article refers to the address: http://
1 System composition and workflow system is mainly composed of three parts: the main station management software module, the main station database module and the PDA field calibration module. The system architecture is shown in Figure 1.
The entire school workflow can be divided into:
• Planning. The master station software generation plan takes effect after a full-time audit.
• Work dispatch. The plan is assigned to each group by the squad leader of each diplomatic class.
• Task download. The school scheduler downloads the calibration tasks to be performed to the PDA.
• On-site calibration. The school staff brought the PDA and the calibrator to the school table for the calibration work. If there is an abnormality at the scene, the wireless communication function of the PDA is connected to the expert diagnosis system of the main station to handle various wiring errors.
• Upload verification results. After the calibration is completed, the calibration staff can upload the verification result to the primary station through wireless or serial communication.
• Count various reports.
2 system implementation
2.1 Design of the main station management software module The main station management software module adopts C/S (Client/Server) mode with high security and stability, reads and writes the master station database, realizes the management of meter and other information, and arranges the school work. , the processing of school table data, the diagnosis of field wiring errors, statistics of various reports and other functions. The development of the main station management software uses Borland's delphi 6 development tool, which has the characteristics of visual development environment (IDE), fast compiler, powerful database support, flexible VCL components, cross-platform development, etc. The favor of program developers [2]. The various functional modules are shown in Figure 2.
Communication module. In the communication between the primary station and the PDA, the data forwarding function of the GPRS front-end machine is used to realize wireless communication, which greatly reduces the attack of the external network on the primary station server. At the same time, it provides an interface with marketing systems and expert diagnostic systems.
System Management. The department and the staff under each department can be set in the system, and the corresponding menu permissions can be assigned according to the level of the personnel.
File management. Operators can manage information such as departments, meters, substations, users, and areas, and provide operational log queries.
Task management. It includes the generation of scheduled tasks, the download of calibration tasks, and the uploading of calibration results.
Report management. Various reports and intuitive charts are provided for the actual needs of the metrology institute.
2.2 Master Station Database Design The master station server installs the Oracle 8i database. Oracle Database is one of the most widely used relational data systems in the world with its security, compatibility, high availability, high productivity, and multi-threading capabilities [3]. The database belongs to the underlying shared data resource support layer in the whole system, and provides support for the storage, management, and query functions of the basic data for the upper layer application. The database includes customer table, substation table, line table, meter table, measuring point table, task table, plan table, check result table, etc. The structure design of the profile is shown in Figure 3.
2.3 Software and hardware design of PDA calibration module
The PDA calibration module includes a calibrator and a PDA with a GPRS network card. The calibrator is used for verifying the meter and the PDA is used to store the calibrator data and the data communication with the master station.
The PDA calibration software is designed with reference to the standard [4] and the actual verification process. The software module provides an interface to manually input visual inspection information, such as whether the meter case is intact, whether the current range is normal, whether the current is lost, whether the voltage is lost, whether it is overloaded, etc.; receiving the meter data through the serial port to the infrared communication mode; receiving the calibrator through the serial port (PWS) data, if it is a PWS with infrared, can receive PWS data through the front infrared port.
The PDA software provides two ways to communicate with the primary station:
• GPRS communication method. The PDA performs wireless communication with the server of the primary station at the checklist site, and obtains information and uploads results in real time. If the wiring is abnormal, the real-time diagnosis and processing is performed by the primary station;
• Serial communication method. Connect the PDA and the client with a serial cable, and obtain the work content and upload the verification information through the client connection server database.
A small database is also built on the PDA to store data such as meter information, meter information, and school task information. The PDA software is developed in the EVC 3.0 environment, and the module structure is shown in Figure 4.
3 System functions and features Compared with the traditional electric energy meter field calibration, the system has the following features:
• School automation. The collected data is automatically input to the PDA through serial port or infrared communication, and stored in the PDA, and then uploaded to the main station database, achieving paperless and automated operations.
• Intelligent school schedules. The faulty wiring expert diagnosis module provided by the system can assist the calibration staff to make wiring error judgment through the GPRS wireless network to improve work efficiency.
• Rationalization of mission arrangements. By generating the annual plan algorithm, combined with considering the user type, the planned completion situation last year, the user area and other information, the school location, the time-sequential user or the substation can be arranged on the same day, avoiding the school staff to work hard.
• Standardization of management. Operators have different management rights, which facilitates the work of the measurement staff in different positions, and at the same time ensures the security and accuracy of the system and data.
• Handling informationization. All the results of the calibration are finally summarized into various reports, such as the energy meter running point verification report, the gate energy meter running point verification report, the energy meter running point non-excellent verification report, the gate energy meter running point non-excellent verification report, Important electric energy meter operating point second rate report, verification result statistics, verification result analysis, etc. Moreover, all of these statistical reports have corresponding statistical charts that intuitively and conveniently present various information to the operator.
• Network security is strong. The system adopts firewall technology and VPN technology, which can prevent the attacks on the primary server from being shut out and ensure the security of the system.
• Real time is strong. The GPRS network has the characteristics of short access time, high transmission rate and high resource utilization [5], which meets the real-time, fast and stable requirements of the system.
4 Conclusion Combining PDA and GPRS technology, the energy meter on-site calibration and management intelligent system, the system is easy to maintain, simple to operate, easy to expand, compared with the traditional calibration method, the paperless paper work and intelligent management. Simplify the work of school calibration, standardize the maintenance of information data by measurement units, and reduce the incidence of disputes and accidents. The system has been put into use in a city in Zhejiang, and has received attention and praise. It is believed that in future applications, it will bring greater economic and social benefits.
Dj Speaker,Portable Bluetooth Speaker,Lf600 Multifunctional Speaker,Speakers For Large Events
NINGBO RFUN AUDIO TECHNOLOGY CO.,LTD , https://www.mosensound.com