Research and development of management information system for power generation enterprises based on workflow technology

Traditional power generation enterprise management information systems have many shortcomings, such as not supporting business processes. This paper combines workflow management technology with management information systems to develop a new type of power generation enterprise management information system based on workflow technology. This paper introduces the overall structure of the system, the division of data processing systems, the design of database systems, the design of data interfaces, the design of workflow management subsystems, and the design of system security. The system has both the advantages of office automation and the characteristics of traditional management information systems. It realizes the management of enterprise business processes and ensures that the system can still operate effectively when the organizational structure and business processes of the enterprise change.
Keywords : power generation enterprise; workflow technology; management information system;

Research and development of power plant management information system based on workfolw technology

Luo Zheng-jun ¹ , Yao Jian-gang ¹ , Luo Dian-sheng ¹ , Yao yao ² , Liu Qi ² ,

(1. College of Electrical and Information Engineering, Hunan University, Changsha 410082, China 2. Hunan HDWL Electric & Information TECH CO.,LTD, Changsha 410012, China)

Abstract : Traditional power plant management information system contains some shortcomings such as not supporting. A new power plant management workflow information system based on the workflow technique is developed, which integrates the workflow technique with management information system. The structure of the system, the designation of the database, data interface, workflow management system and system security are introduced. The system owns both the advantages of the OA and traditional management information system. It can manage the power plant workflow and guarantee that the system can operate effectively when change occurs in the workflow and the organization structure.
Key words : power plant; workflow technique; management information system

0 Introduction
In recent years, with the reform of the power market, competition among power plants has intensified ^[1] . In order to improve production efficiency and gain an advantage in the competition in the power market, each power plant has invested a lot of manpower and funds to build a management information system. However, the traditional management information system has many shortcomings, such as poor scalability, difficult maintenance, difficult to integrate with the internal Intranet or external Internet, poor reusability, and no support for business processes. It is obvious that it can no longer meet the necessary conditions for the development of power generation enterprises under the current power market conditions. The application of new enterprise management models and management information systems has become a necessary condition for the survival and development of power generation enterprises, and it has also become an important step in improving the technical support system of the power market.
This paper combines workflow management technology with management information systems and proposes a new power generation enterprise management information system (abbreviated as WFMIS) based on workflow technology ^[2,3] . The system adopts a database-based workflow technology, which has both the advantages of office automation and the characteristics of traditional management information systems. Based on the actual development of the second phase management information system of Leiyang Power Plant in Hunan, this paper introduces the specific implementation method and steps of WFMIS in detail. 1 Overall structural framework of WFMIS system Figure 1 is the overall structural framework of WFMIS system. The bottom layer in the figure is the database system, which is the foundation of WFMIS system; above it is the data processing system, which is the most basic and most arduous work content in the whole system.

2 Division of data processing system
Data processing is the most basic and arduous work content in WFMIS. It collects various basic data, classifies and stores them, processes them, makes reports, processes them, and provides a basis for the leadership to assist in decision-making. Therefore, it is the basic project of WFMIS. At present, data processing is developing in the direction of online transactions (OLTP), which requires the use of computers as tools to directly carry out business processing work, and completes data collection and sorting while working. It requires the system to have high reliability and rapid response capabilities.
The main task of data processing system design is to divide the relevant subsystems according to the system's requirements for data processing functions, give a brief description of the functions of each subsystem, and describe the data flow relationship between each subsystem.
The division of subsystems will follow the following principles:
(a) The subsystems are relatively independent in logic;
(b) Maximum cohesion and minimum external coupling;
(c) Consider adapting to the business management system of power generation enterprises as much as possible.
In the second phase of the Leiyang Power Plant project, WFMIS divides the data processing system into two major parts: production management and business management, with a total of eight subsystems. The production management part includes: real-time information query subsystem, equipment management subsystem, engineering project management subsystem, production technology management subsystem, and material management subsystem; the business management part includes: planning management subsystem, operating cost analysis subsystem, and system maintenance subsystem. 3 Design of WFMIS database system 3.1 Data object division WFMIS system is a large-scale system based on database. Establishing a stable data foundation is one of the most essential tasks of WFMIS construction. The informatization of an enterprise is the process of transforming the chaotic and disordered data environment of an enterprise and gradually establishing a high-end data environment. Any part of the LDWFMIS system is directly related to the database. The quality of database design not only affects the stability and security of the system, but also greatly affects the operating efficiency of the system. This system starts from this point, conducts data modeling on the basis of comprehensive data analysis, strives to meet the database system design specifications, and designs an efficient information retrieval system database. WFMIS uses Oracle8i, a large-scale relational database that supports object-oriented as the database system software, adopts relational object-oriented data design, regards each system as an object, and fully expresses the data elements and data relationships of each object in the database design. The entire power plant database can be composed of several categories of objects, such as power plant objects, power plant equipment objects, power plant inventory objects, power plant configuration objects, power plant sub-item objects, etc. After comprehensive data analysis, it is found that the above objects are divided into two basic types: one is process-oriented data objects, and the other is equipment-oriented data objects. Process-oriented data objects mainly regard the entire system as a system composed in a certain order, which contains information such as equipment and documents. It mainly describes the system from a spatial perspective. For example, a power plant object. Equipment-oriented data objects regard the system as composed of objects of some equipment types. Each static object is composed of many data elements, including the unchanged and variable information of the equipment, such as power plant equipment objects and inventory list objects. 3.2 Logical division of the database In order to ensure the independence and security of each data processing subsystem, the WFMIS database is divided into eight logically independent databases according to the division principle of the data processing system. In fact, they are called eight schemes in ORCALE8i. Each scheme corresponds to a user, and only the user has all the operation permissions for all database tables in the scheme. Since the logical databases cannot access each other in principle, but the exchange of some data information between systems is inevitable, the data information exchange between the logical databases is completed through the corresponding authorization of the users of each other between the schemes. 4 Design of system data interface Due to the position of WFMIS in the entire power plant system, a lot of data in the system comes from some other existing systems, such as the power plant monitoring information system (SIS), financial management system, graphics system, dispatching, SCADA, etc., and each system uses the database as the background. Due to the different network environments and database types of each system, there are interface problems with this system. In addition, in order to enhance the compatibility and expansibility of the system, there are also programming interfaces in the software. The interfaces between this system and other systems exchange data through the gateway workstation. The reserved interfaces with other software are all standard programming interfaces. Figure 2 is a data interface structure diagram of the WFMIS system in the second phase of the Leiyang Power Plant project.

3 Key points of
software system programming design This system uses Visual C++ as the development platform. By using the characteristics of object-oriented language, it can avoid information redundancy in the description, enhance the use and management of knowledge, and facilitate maintenance. 3.1.1 Power grid objects
The dispatching operation roughly divides the operation of the equipment into four states: "maintenance", "cold standby", "hot standby" and "operation". According to the different number of equipment states in the dispatching operation terms, the primary equipment can be divided into the following categories: four-state components: switches, capacitors, low-voltage reactors (maintenance, cold standby, hot standby, operation); three-state components: high-voltage reactors (maintenance, cold standby, operation); two-state components: switches (open, close), transformers, busbars, outgoing lines (maintenance, cold standby); non-operating components: generators, connecting lines in substations.
3.1.2 Dispatching command ticket objects
Each dispatching command ticket not only has a series of operation statements, but also has something to do with the state of the substation before and after the operation. Therefore, when establishing the dispatch order ticket object, it is also necessary to consider recording the power grid operation status before and after the invoice is issued.
3.2 Determination of classes and their object attributes
3.2.1 Electrical component class and its derived classes
Using the characteristics of OOP, the inheritance relationship of each equipment class is determined, and the parent class - the basic component class is abstracted according to the common attributes of each electrical equipment, and then different electrical component subclasses are derived. Other equipment classes that cannot be operated (such as line and text classes) are encapsulated to prevent misoperation.
The basic component class has the common characteristics of all component classes. While inheriting these common characteristics, each derived component class has its own unique attributes, which together constitute a collection of electrical component classes.
3.2.2 Determination of object attributes
First, start with the most basic component object class. The basic component class is the parent class of all component classes. The attributes it should have include component name, component number, component attributive (used in the dispatch order ticket), and the coordinate position of the corresponding graphics of the component on the interface.
The derived class also has other attributes. The attributes of the four-state component include: the definition of the four states, the current state and the past state, and the four-state operation rules; the attributes of the three-state component include: the definition of the three states, the current state and the past state, and the three-state operation rules; the attributes of the two-state component include: the definition of the two states, the current state and the past state, and the two-state operation rules.
The attributes of the substation include: the name of the substation, the current state of the station (from the perspective of computer operation, whether the station is in an activated state), the status of the equipment in the station, the status of the secondary protection equipment in the station, and the chain data set of various components. The power grid is composed of substations, and its main data is the chain data set of the substation class object.
At the same time, in system development, the dispatching command, dispatching task, and the change record of the power grid operation state before and after the operation should be regarded as the attributes of the dispatching command ticket object, that is, data.
3.3 Programming implementation of class objects and methods
3.3.1 Implementation of class objects
The programming language describes each basic component class and derived class, and the derived class automatically inherits the attributes of the basic component class. For example, the implementation of the basic component class:

3.3.2 Implementation of class methods A
method is a unit of code defined in a class that describes the operation of the object on its data structure and the algorithm for the object to perform operations.
The various class methods designed can be divided into the following categories: object construction methods, including general constructors and destructors; basic attribute setting and acquisition functions; class name identification functions; object deletion methods; and others (methods set to achieve specific functions).
For example: a function of the switch class, its function is to detect the status of the switch according to the definition of the switch.

3.4 Graphic interface function design
3.4.1 Graphic display
From the object-oriented point of view, take a single electrical device as the basic class object, and the primary main wiring diagram of the substation displayed on the computer screen is a combination of the corresponding graphics of these single electrical devices.
First, create a bitmap resource for each device object class to represent the undefined state when the device is not put into operation. In addition, design the corresponding bitmap resource according to the different device states. When drawing the primary wiring diagram of the substation, fill in the component code, component number and component attributive at the corresponding coordinates in a grid marked with vertical and horizontal coordinates according to the on-site situation. The system uses the coordinate positioning method according to the coordinates and component code to display the component and component number at the corresponding position.
3.4.2 State change of component graphics during operation
The dispatching operation in the power system is a series of operations to change the operating state of electrical equipment for a certain task. The graphical interface of this invoicing system has a click operation function. To change a component from state A to state B, click the left mouse button on the component graphic. The system determines the coordinate value of the small area to which the clicked position belongs, finds the data record of the component object based on the coordinate value, and obtains the attribute values ​​of the component such as the name, number, and current state. Then, a dialog box pops up on the interface to display the component attribute value, and the operator can change the component state in this dialog box. After confirmation, the state value of the component object in the system will also change accordingly.
3.4.3 Setting of operation rules
The rules are stored in the component class object in a certain data form. When operating, first search for related components to see whether their states meet the requirements of the rules, and then determine whether the operation can be performed safely, that is, the operation rules are expressed in the form of restricting certain component states. Each operation rule may have several restrictions, and the operation can be performed as long as any one of them is met. Therefore, the setting of the operation rules is changed to the restriction of the status of the related components, and each rule is set as a row. The rule setting input interface is shown in Table 1. Each row represents a restriction condition, and every three columns represent the state of a specified component.

Each row of condition setting will perform the following logical operation:


OR operation between rows can get the final logical result:
RESULT=(Result1)or(Result2) …or(ResultN)
If the result is true, this operation can be executed, and if the result is false, this operation cannot be executed. 4 Conclusion This power grid dispatching microcomputer invoicing system has been put into operation in East China Grid Dispatching. From the operation situation, the system has stable performance, flexible and simple operation, fast ticket issuance speed, good versatility, and can not only ensure the completion of dispatching order ticket generation and management under the current operation mode, but also adapt to the changes in the power grid system structure and the addition of substations. The system has a high application and promotion value in the generation and management of dispatching order tickets.