Çerkezköy-Kapıkule demiryolu elektrifikasyonu scada sisteminin incelenmesi

Abstract

Demiryolu elektrifikasyonu lokomotifin pantografına teması sağlayan katener, katenere enerji veren trafo merkezleri ve bunların uzaktan kumandasını sağlayan SCÂDA sisteminden oluşur. Giriş bölümünde ülkemizde demiryolu elektrifikasyonunun tarihçesi verildikten sonra ikinci bölümde katener ve üçüncü bölümde de trafo merkezleri hakkında özet bilgi sunulmuştur. Dördüncü bölümde SCADA sistemleri ve projede kullanılan Cromos adlı SCÂDA sisteminin ilkeleri verilmiştir. SCÂDÂ Danışmalı Denetim ve Veri Toplama anlamına gelen bir kısaltmadır. Çerkezköy-Kapıkule projesinde Cromos adlı bir SCÂDÂ sistemi kullanılmıştır. Cromos sisteminde MT700 uzak uç birimleri (RTU) kullanılmıştır. RTU' lardaki kartlar arasında MT Anayolu aracılığıyla iletişim sağlanır. MT50 ve MT84. RTU 'nun beyni olan işlemci kartlarıdır. MC57 iki kanallı seri arabirim kartıdır. MT91 kartıyla devre kesicilere kumanda edilir. MT72 ve MT41 sayısal giriş kartlarıdır. Örneksel girişler için MT70 kartı kullanılır. Telemetri sistemi RTU'laria denetim merkezi arasında arabirim olarak iş görür. Denetim merkezinde arıza olasılığına karşılık çift bilgisayar bulunur. İşletmenler komutlar fare ve renkli ekranları kullanarak verirler.

Mam parts of railway electrification are overhead contact system (QCS), transformer substations, neutral sections, switching posts and remote control equipment. The OCS used in Cerkezkoy-Kapikule railway section consists of messenger wire, contact wire and droppers. Because of difficulties in production and maintenance the catenary is divided into parts whose lenghts are not over 1200 m. Overlaps are used to join two adjacent line parts. Some overlaps are air insulated. The line part between two cf them is named a section. Sections can be de-energised and grounded even when the adjacent ones are not. The voltages in transformer substations are not in phase with one another. Air insulated over laps are short circuited while a pantograph is passing under them and voltage sources whose phases are different are connected to one another. To avoid this danger two air insulated overlaps with two isolators across them are located one after another and named a neutral section. Switching posts are small AC switchgears containing load breakers and isolators to carry out electrical manoeuvres. Load breakers and isolators can be operated either locally or remotely. Power transformers are located in transformer sub-stations. Circuit breakers, load breakers and isolators connect power transformers to the catenary. Isolators saust not be operated when current is flowing through them, so some interlocks via relays are used to avcı d m ı souer a t ı on The word SCABA is formed from the initial letters of the words: Supervisory Control XI 11 And Data Acquisition. The typical purpose of a general SCADA system is to enable an operator to remotely monitor and control the plant items, valves, circuit breakers, meters etc. A SCADA system generally consists of a central or master control unit, master station, connected to one or more remote data gathering/control units, outstations or Keaote Telemetry Units (RTU). The configuration of the connections may be very complex or very simple as in a single multi-drop system where all the RTUs are connected to the same communications link. Information from the plant may be of two types, digital signals or analogue signals. Digital data is data that may take one of two different values, on or off, high or low, etc. Analogue data varies over some range of values, such as the current in a wire between an upper limit and lower limit. Cromos is the name of the SCADA system used in Çsrkezkoy-Kapıkule Project. There are three sections in a Cromos system: The Outstations The Telemetry System The Master Station The outstations are located in transformation substations, neutral sections and switching posts. The main function of an outstation in a Cromos system is to provide an interface between the outside world, i.e. the plant and the master station which controls the plant. The outstation gathers data from input devices, such as sensors, relays, transducers, circuit breakers, etc. The data is gathered according to a pre-programmed scan philosophy and is stored in a database within the outstation which can be accessed by the master station. The outstation can also control outputs according to instructions from the master station. Buses are used to connect two modules. There are two types of buses: parallel and series. The HT bus is a parallel bus and is located along the upper portion of the cardframe backplane in an outstation. It provides data, address and control lines between the processor and the I/O cards. :iv The HT bus and any input/output cards on it can be monitored and driven manually by the MT99 MT bus diagnostic card. As a bus cannot be driven by two cards when MT99 is placed in test mode the MTSO or MT84 card must be removed. The HT50 and MT94 are microprocessor based controller cards. RAH and PROM memory sizes, the baud rate and the outstation address are set on the cards with switches. The MC57 is a two channel serial interface card. Each channel, A or B, is separately configurable, having both software and hardware settings. The HT91 is used to control to circuit breakers and has eight digital inputs and eight digital outputs. As a circuit breaker needs two digital inputs and two digital outputs, a card can control four circuit breakers. The output is active for a short period only, i.e. it is a pulsed output. At any one time only one output may be active. It is a high security control card so an output must be selected first and then actuated via a second common actuate relay. If two relays are selected then the "two up" detection circuit prevents the actuate relay from energising. The MT72 and HT41 are digital input boards. The MT72 has 32 inputs and the MT41 has 16. Each of the inputs is cpto isolated. Switches enable card address to be set on the card. The &T?Q is a 12 bit signed analogue to digital converter with eight multiplexed input channels Parallel signals are used both within the outstaticns and within the mastar station and serial signals are used in the telemetry system, UARTs convert between serial TTL signals and the parallel signal format. They also check for the correct byte structure. ¥hen the master station sends the messagge ail cutstations on the line receive it, So outstation addresses are used to ensure correct routing. The main parts of the master station are the computer suite, the two operator workstations and the overview mimic diagram. The computers used by Cromos are Intel Svstem 320 units which are based uocn the xv Intel 336 processor. The system incorporates the iRMX real time operating system, high capacity mass storage and high density RAM boards. In addition to the 80386 general purpose microcomputer, the system provides a 80387 numeric co-processor. The ıSBC 188/56 within the computer is an intelligent communications controller which act as a single board communications controller or an intelligent slave for communications expansion. The computers form a hot standby system. In a hot standby system there are two computers, normally arranged so that one computer, termed the online computer, is connected to communications and peripherial items and the second computer, termed the standby computer, is powered up and active, but not connected to the communications system. In the event of a failure in the online computer the standby computer will automatically connected to the communications and peripherals through the failover system and as the standby computer contains the same data as the online the change is achieved with minimum disruption of the control operations. The System Status Panel has three functions: to indicate the status of both computers to enable manual failover to be carried out to enable controlled failover to be carried out Overview mimic diagram contains the single line diagram cf Çerkez koy-Kapı kule section with LEDs on the circuit breaker symbols and presents to the operator the state of the plant. Cromos system maintains configurable user names each with individual configurable passwords, k user name is configurable to one cf the four levels cf user access: display, operator, supervisor and engineer. In operator workstations there are two screens: the left screen and the right screen. The left screen is used to display most of the information required by an operator or engineer. Most important pages are outstation pages, alarm page, alarm list, analogue page, plant page, event log and trend disoiavs. xvi The right screen is normally used to display the AC Overview page and AC Interconnect i vity page. The AC Overview page is almost the same as the overview mimic diagram. The AC Interconnect i vity page shows from where the catenary sections are being fed. For each input, output, outs tat ion and circuit. breaker etc. a database proforma must be filled.