Reducing the Costs of Electrical Energy in the Copper Mining and Smelting Complex RTB Bor by the Use of Distributed Control System Viša Tasić 1 , Dragan R. Milivojević 1 , Marijana Pavlov 1 , Vladimir Despotović 2 1 Industrial Informatics Mining and Metallurgy Institute Bor Zeleni bulevar 35, Bor, Serbia Phone: 381(0)30435109 Fax: 381(0)30435175 E-mail: visa.tasic@irmbor.co.rs 2 Technical Faculty of Bor University of Belgrade Vojske Jugoslavije 12, 19210 Bor, Serbia Abstract - Monitoring and control of consumption of electricity for great consumers, such as Copper Mining and Smelting Complex RTB Bor (Serbia), requires synchronized actions in different production plants. First of all, it is necessary to achieve an effective exchange of actual information between the production units and control centers. The responce time has to be small enough in order to implement timely impact on the reduction of peak power at the consumer transformer stations. Such control systems can be classified as soft real time systems. The fact is that for large customers reduction of peak power on a monthly basis for only 1% is reflected in substantial financial savings (in the order of magnitude of thousands of euros). This data justifies the need for existence and proper functioning of these control systems. The paper presents results of development and implementation of our own solutions for distributed systems management of electricity consumption, both at the company level and in each individual production plant. A special attention is paid to presentation of the software solutions, as well as achievements in practical implementation. I. INTRODUCTION Copper Mining and Smelting Complex Bor (RTB Bor) is one of the greatest consumers of electrical energy in the Republic of Serbia. The consumption in its production facilities (mines, flotation, smelter and refining plants) is about 50 GWh per month, which amounts about one million euros, including the costs of peak power. Certainly it is not necessary to emphasize other reasons for introduction of regular measures for reduction of these costs. In addition to frequent regulatory and organizational actions, realization of the real time based system for monitoring of electrical power consumption in RTB Bor started in late 80's. Because of the large complexity, a great number of transformer station and their spatial dislocation, project included only main substations (two of them in Bor and three in Majdanpek) in the first phase. Although the monitoring system justified its development and financial investment, its expansion didn't continue until several years ago when new transformer substations were covered as well. Department of Industrial Informatics, at the Mining and Metallurgy Institute Bor has been designing real time systems for monitoring and control of industrial processes since 1990. Three generations of Microprocessor Measuring Station (MMS) have been developed. Fig. 1.The power transducer connection MMS is industrial PLC (Programmable Logical Controller) and it is a core of process control system [1]. Serial communications are performed using specially designed logic and communication protocol developed for this purpose. Although MMS can be an autonomous system unit, it is more frequently used as a node in a simple network (entity), which contains MMS and PC workstation. The complex communication subsystem on both sides was developed for efficient entity functioning. Main objectives of such systems are real time data processing, results presentation (in the form of dynamic synoptical schemes, real time graphs and tables) and database management. Appropriate software application has been developed for monitoring of power consumption and power peak control at Copper Mining and Smelting Complex Bor [2-4]. II. DISTRIBUTED CONTROL SYSTEM A. Hardware Characteristics Measuring power transducer is integrated in each cell of the transformer substation, connected as shown in Fig. 1. The power transducer (Fig. 2) gives the standard current signals (4-20 mA) as an output, proportional to the active and reactive power, with less then 1% nonlinearity (using Aron′s measuring methods).