OPEN SUBSTATION AUTOMATION SYSTEM (OSAS)

Prepared By: Shamsheer.T

Electrical Engineer

Energy & Power Contracting Co. Ltd.

Al khobar-KSA

Contents

Introduction

Substation Automation Objective

Traditional SCDA System

OSAS Concept & Components

OSAS Overview & Architecture

OSAS Applications

OSAS Implementation

Merits of OSAS

Introduction

Substation automation was introduced over the last 30years More than 4000 systems have been installed word wide. This was based on proprietary serial communication with

conventional copper wiring. With advent of IEC61850 there is a comprehensive global

standard for all communication needs in the sub station being introduced now.

IEC 61850 Very big commercial impact “saving millions of dollars”

Substation Automation

Objective of automation:

Control

Monitor &

Protect ionsubstation equipment must be monitored and controlled for increased

reliability, reduced fault restoration times, and balanced electrical demand with available generation

Protects high voltage equipments from faults, disturbances, and overloading on the power grid, and optimizes power to utility customers.

Traditional SCADA System

Components: Master station, RTUs, IEDs, transducers & sensors.

Master Station: Provides the primary operator interface and manages overall system functions, collecting and analyzing data from RTUs, as well as initiating control actions.

RTUs: Detects timestamps, and logs set-point and I/O events.

IEDs, transducers & sensors: measure power, energy, voltage, current, etc.

Traditional SCADA System

Traditional SCADA System

Drawback: Expensive

Master station hardware & software are designed using expensive proprietary systems.

Additional investment for training and maintenance

As the RTU is the central device, many features are to be added to improve reliability

RTU enhancements are very expensive

Open Substation Automation System Concept

System comprised of Web enabled software and intelligent IEDs & control devices.

Monitor, record calculate & analyze hundreds of data points in real time

Provide status monitoring

Automatic control, alarm and advanced power quality analysis with OSAS IED.

Open System: A computer system

Open Substation Automation System (OSAS)

Components:

Software Applications Network Communications Intelligent Electronic Devices (IED) Gateways/Servers

OSAS (Compnents…)

Software Applications: A powerful suite of flexible, user friendly software applications and graphical user-interface modules are available. These advanced user interfaces and easy to configure tools enable improved date reporting and database configuration management.

Network Communications: A range of network components are available to tie new and legacy equipment into one unified system. Provide secure and reliable communications media based on experience and expertise in numerous network systems.

IEDs: Any device that incorporates one or more processors Receive or send data/control from or to an external source OSAS IEDs can be programmed to perform automatic control, alarm

and power quality analysis

OSAS Components

Gateways/Servers: Robust system for monitoring and controlling devices as well as for performance automation, IED gateways and host communication functions

Monitors & Sensors: Remote monitoring and critical fault detection is achieved.

Feeder Automation:

Distribution automation remote terminals equipped with auto-sectionalising and automation restoration

Software can dramatically reduce a customer’s outage frequency.

OSAS Overview

System with conventional equipments

Use conventional wiring to the process

OSAS Overview

System with non conventional instrument transformers and modern switchgear

Serial point-to-point connections (IEC 61850-9) from primary equipments to the relays

IEC 61850 Substation Architecture

Substation Automation using OSAS

Feeder A Feeder B Feeder C Feeder D

HUB

Feeder DFeeder CFeeder BFeeder A

OSAS Basic IED

OSAS Advanced IEDGateway

Modem

Service Entrance

Telephone System

RS-485

Substation B

Feeder DFeeder CFeeder BFeeder A

OSAS Basic IED

OSAS Advanced IEDGateway

Radio Modem

Service Entrance

RS-485

Substation C

Radio Communications

Service Entrance Service EntranceSubstation A

Radio Communications Ethernet

Radio Modem

Modem

Control Center

OSAS Advanced

IED Gateway

OSAS Master Station

Breaker Breaker

Breaker

Breaker

Breaker Breaker BreakerStatus input Status input Status input Status input

Status input

Status inputStatus input

Tap Control Tap ControlTransformer

PTCT

Transformer

PTCT

Relay Relay RelayRelay

RS-485 RS-485 RS-485 RS-485

RS-485 RS-485 RS-485

OSAS Basic IED

OSAS Basic IED

OSAS Basic IED

RS-485

OSAS Basic IED

RS-485

ModbusMaster

Application1:Substation Automation using OSAS

Control Center: master station runs operations software on a PC-based windows xp/2000 server

OSAS software communicates to

Substation A via an Ethernet link

Substation B via a telephone modem

Substation C has a wireless radio link to the control center

Substation Automation using OSAS

Advanced OSAS IED: Highly accurate revenue billing

Communication mastering functionality

Control and equipment monitoring functionality

OSAS Basic IED: Monitor each feeder

Provide real time power and energy, power quality, I/O and alarm information

Feeder information is sent back to the master station through Ethernet gateway located in OSAS advanced IED

Application 2: OSAS System to supplement RTU-Based SCADA System

HUBSubstation A

OSAS Advanced

IED

Breaker

Breaker

Transformer

PT

CT

Modbus or DNPOSAS

Basic IEDOSAS

Basic IED

Breaker

PT

CT CT

PT

RS-485

Modbus or DNP

Control Center

Master SCADA

OSAS Master Station

Power Quality Monitoring

Ethernet

Ethernet Ethernet

EthernetRemote Terminal Unit

Modbus or DNP

OSAS System to supplement RTU- Based SCADA System

Traditional SCADA system communicate with RTU

OSAS operations software station ( in master station) communicate directly with the OSAS IEDs

OSAS IEDs Within the substation:

Provide information to multiple destinations

Provide real-time data to RTU then back to SCADA master station

Replace several legacy transducers

Provide real-time data to the OSAS master station through on-board Ethernet port

OSAS Implementation

Implemented in three levels

Level 1: Networks within switchgear

Level 2: Networks within individual S/S

Level 3: Network located in the control center

Level 1:IEDs networked within switchgear or a group of switchgears

E.g. low voltage switchgear networked to a common PLC/gateway by the switchgear manufacturer

OSAS Implementation

Level 2:OSAS scope starts at level 2

IEDs connected via fiber optic cables to Ethernet switches

The Ethernet switches connected by fiber optic cables in parallel redundant topology or bus-ring topology

Each substation shall have:

Operator Automation Station (OAS), data acquisition server and database, substation annunciator, engineering automation station (EAS), event and alarm printer, GPS clock and SNTP server

OSAS Implementation

Level 3:Interconnect the individual SA systems

Provide centralized monitoring and control from the control room

Central control room shall have:

Operator automation station (OAS), dual redundant data acquisition server, historical data server, engineering automation station (EAS),event and alarm printer, hard copier, training simulator, GPS clock and SNTP server

OSAS Substation Architecture

OSAS CCR Architecture

OSAS Block Diagram

OSAS Block Diagram

OSAS Block Diagram

Merits

Lower substation cost

Reduced downtime

Lower equipment maintenance cost

Reduce SCADA system cost

Low initial investment that can meet future needs