IV DAS Pilot Project

2. System Concept for DAS

2-1 System Outline

DAS means the system of performing automatically a distribution network operation by using the computer installed in distribution control center (DCC) after classifying a fault section when a fault is occurred in distribution line, monitoring and controlling the states of the switches being scattered, measuring a voltage and current. DAS can be divided into 4 kinds such as Main server, Communication devices & network, FRTU and Switches as following [Figure 4-2].

System configuration
[Figure 4-2] System configuration

2-2 Components of TDAS

2-2-1 Main Server

As pre-mentioned main server is installed in DCC and has the same function as human’s brain in operating DAS. This is organized to operate stably a system with a using of distributed processing method and collects enormous amount of data from feeder remote terminal units (FRTU), monitor FRTU and send the control order to FRTU, which is possible by a connection of each application program through a middleware. Protocol is DNP3.0 and even if the number of FRTU is increased its system can be operated stably. UPS (5 KVA) is installed in addition in order to protect from a stop of system when a interruption is occurred, also output device unit (Printer) is installed for outputting the various kinds of information.

2-2-2 Communication Facility

This is consisted of two kinds, transmission network and devices. The kinds of transmission network can be divided into wireless network and wire network, wire network include a optic method and leased line, wireless network include TRS, CDMA and GSM/GPRS. For composition of transmission network diverse methods can be used according to the given site circumstance, in this pilot project wireless GPRS (between FRTU and communication station) and wire leased line (between communication station and main server) is used simultaneously.

Transmission facility is consisted of main server and FRTU, which conduct same function as a human’s nervous network and transmit the control order of main server and receive the measuring value of FRTU in the optimum situation. GSM modem, data service (GPRS: General Package Radio Service), CSU (Channel Service Unit) and Router is used as a GSM transmission facility.

2-2-3 FRTU

FRTU (Feeder Remote Terminal Unit) is installed on overhead line together with Gas Insulated Circuit Breaker (for overhead line), which is for the automation of power distribution, to monitor the voltage and current in the distribution line. It detects the change of load current and situation in interruption and transmits the fault information to Server. It also carries out remote control function by receiving command from Server, finally minimize the range of interruption with separating the sound section from the fault section. It stores all the events occurred in the distribution line, providing analysis on the cause of fault. It sends the conditions of the distribution line to Server through DNP3.0 Protocol for remote monitoring and circuit breaker control purpose.

2-2-4 Switches and Controller

G/S is installed in distribution line to use for a line Open/Close and tie-up and it adopts SF6 gas insulation method and it is 3 phase load break switch of simultaneous operation in single tank-type. Its components are body, controller, power and control cable. Body is equipped with auxiliary devices as follows; a manual operating handle, locking device for Open/Close, indicator of operation, indicator of pressure, gas emission device, earthing terminal, counter of operation and gas injecting valve. Controller is consisted of FRTU which can measure and monitor, control part consisted of manual operation, power switch, power facility (AC 220V), battery for control power (12V 2EA, 18AH) and modem.

R/C is the switches to minimize a fault section inputting when a fault is erased or separating the line by repeatedly Open/Close as a frequency designated previously in order to prevent the fault from spreading when a fault is occurred. Internal components is almost same as G/S and R/C adopts a vacuum circuit break method of a digital control. And it is designed and manufactured to be started by an external AC 220V, it is consisted of the vacuum circuit break part installed in a stainless steel tank, body with Magnetic Actuator and control box and it is connected with a separable shield control cable each other. Insulation SF6 gas is filled inside of body and series battery 2EA (DC 24V) for a control power is installed in a controller. Also body have auxiliary devices such as an earthing terminal, manual handle, gas injection valve, indicator of operation and counter of operation.

2-2-5 Simulator

Simulator provides the DCC staff with opportunity to practice the operational procedures of DAS under simulated conditions. Through these opportunities, the staff can get rid of the fear of making mistakes on a real situation. The simulator has the same distribution system in its configurations so that the center staff can get used to DAS procedures. This has made enormous contributions to the efficient operation of DAS.

2-2-6 Application program

Application programs installed in Main server are Nzed, Nzed Editer, Agwork of middleware and AgOLD being used by KEPCO in present.