Implementation of a Test System based on OPC Server for Development of Electronic Speed Governor in Gezende HEPP Dogan Gezer, Cem Sahin, Abdullah Nadar, Abdullah Altay TUBITAK UZAY Power Systems Department, METU Campus, Ankara, Turkey dogan.gezer@uzay.tubitak.gov.tr, cem.sahin@uzay.tubitak.gov.tr, abdullah.nadar@uzay.tubitak.gov.tr, abdullah.altay@uzay.tubitak.gov.tr Abstract Speed governors (SG) are auxiliary devices to measure and regulate the turbine speed where the turbine is coupled to a synchronous generator. A rehabilitation project for Gezende HEPP has been signed at the end of 2010 covering renewing of SG and excitation system of the plant. SG could be divided into two subparts; hydraulic speed governor and electronic speed governor (ESG). In order to develop ESG in factory within the conditions close to the field, a test system based on Matlab/Simulink and intelligent I/Os will be designed and implemented. Before production of ESG cubicles and execution of tests with real signals, it is possible to develop and test ESG in a setup using OPC Server. In this paper, the test system designed and implemented based on OPC Server for the development of ESG will be explained. Index Terms—Hydropower Generation, Electronic Speed Governor, Test System, OPC Server 1. Introduction Gezende HEPP is a 20 year-old hydropower plant which is situated in the southern part of Turkey on Göksu Stream with 3x52 MVA of generation capacity. Turkish Electric Power Generation Incorporated Company (EUAS) and Scientific and Technological Research Council of Turkey (TUBITAK) have signed a rehabilitation project to renew the SG and excitation system of the plant in order to successfully satisfy the ancillary services requirements of Turkish TSO. The basic function of a SG is to control speed and/or load [1]. SG brings the turbine speed to the nominal speed before synchronization to the network and after synchronization is completed, SG is used to control the active power output of the unit in one of the operation modes among speed control, opening control and active power control. There are many studies concerning speed governors and test systems in general. In [2], relevant features and conditions are defined for a test system to be used during the design and test process of ESG. Signals of simulation model of a turbocharged diesel engine in Matlab/Simulink are sent or received via Matlab/xPC target toolbox through I/O interface circuit test system in [3]. Test system with different communication connections such as RS-485 and CanBus for a diesel engine is told in [4]. By the usage of the test system with OPC Server, critical points listed below are checked:  Logic diagrams used for ESG  Wrong alarm, trip and threshold values  Logic diagrams of ESG against fault conditions formed by the test system  Buttons, trends and lists in HMI screens Following Section I, hardware, software and communication components of the test system will be explained in Section II. Design and models of the test system will be told in Section III. The concluding remarks are given in Section IV. 2. Features of Test System SG is composed of hydraulic and electronic parts. Hydraulic Speed Governor (HSG) includes high pressurized oil system, various valves and servo cylinders. This equipment are used to provide sufficient oil pressure, to manipulate pressurized oil to the servo cylinder or to the oil tank and to make wicket gates to move in desired range. ESG sends the desired operation point to the driver of the servo cylinder. Also, ESG is a signal interface between the SCADA system of the plant and HSG. Relevant measures and status signals reach the SCADA system via ESG and set points given by the operator of the plants is realized through ESG. Using test system with OPC Server, all signals coming from control room and the SCADA system of the plant to the current ESG will be created in the memory area of programmable logical controllers (PLC). Similarly, all the signals from ESG to SCADA system of the power plant and control room will be formed and all related parts and equipment of the plans will be modeled. A critical point in this rehabilitation projects is that existing SCADA system is not being rehabilitated and this requires that the new ESG signals should be compatible with the remaining ESG. 2.1. Hardware Hardware of the test system consists of simulation computer, network switch, PLC and Human-Machine Interface (HMI) screen. Simulation computer has two important features in the test system: Simulation software and OPC Server are installed in this computer and communication of OPC Server with PLC is achieved via this computer’s network interface. ESG is developed in PLC platform. The logic diagrams for SG are run on PLC. Although in real ESG signal transfer is done via I/O modules, in test system based on OPC Server, signal transfer is done on PLC’s memory area. In Table 1, the test system signal numbers are given. Among the signals classified below, there exist status signals which are received by ESG coming from both the SCADA system of the ELECO 2011 7th International Conference on Electrical and Electronics Engineering, 1-4 December, Bursa, TURKEY 153