SAS(Substation automation system) is suitable for centralized collection of data and information. It offers many distinct advantages to the user such as
*Modular and multiprocessor architecture
* Easy maintenance
* Easy expandability
* Common, integrated engineering tool for all products of SICAM AK3 family
* Versatile communication capabilities
The State of the Art control system for substations require usage of fast, powerful microprocessor based systems designed to function in the process environment in a functionally decentralized manner. The tasks of such systems are manifold and they have to guarantee safe and secure operation of the entire system with high availability and shortest repair time.
The proposed system comprises the following main components:
GATEWAY based on SICAM AK3 ACP product platform. The SICAM AK3 products are designed to cater to the specific requirements of transmission, sub transmission and distribution segments. These control units are provided with requisite number of processing and communication elements for interfacing with the Numerical Relays and MFMs. After collecting the information from Numerical Relays and MFMs, it transfers all the information in required manner to different control centers via GATEWAY.
Human Machine Interface (HMI) is a standardized control room computer system based on SICAM SCC HMI system with scalable expansion capabilities. It is a server/PC based, full graphic HMI providing logging, alarming and archiving functions.
Communication interface consists of two levels – one between the Numerical Relays, MFMs and GATEWAY and second between GATEWAY and control centers as well as HMI. The protocols used in the proposed system are standard protocols like IEC 61850 for protection relays, Modbus for MFMs, IEC 60870-5-104 and IEC-101.
Numerical Protection Relays are based on Siprotec family of relays are provided for protection of the switchboard and CRP. They are taking status from the field and reporting the same to the GATEWAY
The Substation automation system is suitable for centralized collection of data and information. SAS is interconnected with all the Numerical Relays via Ethernet Switch and MFMs by RS-485 cable . Analog data is coming via MFMs on modbus protocol and protection signals are reported to AK3 ACP via Numerical Relays on IEC-61850 protocol. The two Gateways (AK3) are placed in the redundant configuration in the event of failure of one the other will act as the main. The redundancy is maintained by the two unit of EMIC modules.
The SAS system monitors signals and measured values so that when these assume the specified status values or when they exceed or drop below the mentioned limits, the system activates an alarm as well as logs in the hard disk and initiates automatic printing as and when required. At process level protection devices, which are IEC 61850 compliant, are interfaced with SICAM AK3 Gateway and SICAM SCC Main-Redundant Servers via Ethernet switches over fiber optic medium in ring topology.
The configurable switches use RSTP (Rapid Spanning Tree Protocol) algorithm to provide redundancy to the process connectivity. A single failure of Ethernet on the ring does not disturb BCU/Protection device communication to the SICAM AK3 Gateway & SICAM SCC Main-Redundant Servers. The adopted architecture allows for high availability and quick error detection in the case of a failure of a device or a break in a fiber optic connection.
The SAS system monitors signals and measured values so that when these assume the specified status values or when they exceed or drop below the mentioned limits, the system activates an alarm as well as logs in the hard disk and initiates automatic printing as and when required. The system supports the remote control features. The remote control/ switching command can be given by the operator by selecting the equipment on SAS screen. The system provides for handling dynamic display of process parameters as well as functions like user password entry, system diagnostics and parameterization etc.
The data collected by the SAS (including the current status of all the processed signals) is available on the respective screens. The representation of various distribution networks in the form of mimic diagrams on the screen shall be available. The system includes features for checking the healthiness of the system and communication links. It provides continuous reliable operation with the hardware (being suitable for installation in Control Room Environment).
A separate Laptop is provided for disturbance recording and analysis software. For that the laptop should be connected on substation LAN, whenever a fault occur a comtrade file is created in the relay. And the same gets transferred to the Laptop for further fault analysis.
The GATEWAY based on AK3 ACP has high functionality and flexibility, through the implementation of innovative and reliable technologies, on the stable basis of a reliable product platform. The GATEWAY is configured to perform two functions:
*Centralized acquisition of data and information.
* Interface with the HMI and Control Centers.
GATEWAY AK3 is working in the redundant fashion which collects data from feeders of the switchyard as soft signals through Relays and MFMs and will process them. The GATEWAY has a multiprocessor architecture and firmware principle using 32 bit processor technology. It can combine different elements for:
* Serial communication,
* LAN/WAN communication,
This architecture ensures easy expansion at later stage without reduction in performance. The Main RTU unit provides a number of possibilities for the automation of widely distributed process, and is the most powerful device of the SICAM RTU’s product family in terms of communication, automation functionality and redundancy. It supports system features like complete backup on an interchangeable flash memory card. In the AK3 ACP a flash card is used for storing parameters, so that exchanging devices is a simple Plug & Play operation. The configuration is transferred to the spare device with the flash card. As a result, loading from a PC is not necessary and the correct parameters are always available locally. This will permit comprehensive remote diagnosis options, and down times.
The GATEWAY provides the following elements:
*Master control element
* Processing- and communication elements
* Protocol elements
Master Control Element
GATEWAY consists of a master control element which provides the central hub function for all connected basic system elements. The master control element operates as bus master with one electrical Ax 3 peripheral bus. It also caters communication via installable protocol elements to any superior or subordinate automation unit. It acts as a centrally coordinating element for all system services like Data flow control, Control function, Diagnosis, Time management, Saving parameter and firmware onto flashcard.
Processing and communication elements
They provide functions like open- and closed loop control function in accordance with IEC-61131, Telecontrol function, Communication with other automation units (AU) via protocol elements, communication with peripheral elements via Ax 3 peripheral bus (Ax-Bus)
The protocol elements are required for data exchange with other automation units or control systems. The exchange is carried out via telegrams. The standard of communication is in accordance with the standard protocols like Modbus, IEC 60870-5-101, IEC-61850, and IEC 60870-5-104 (Ethernet, TCP/IP). The internal communication from/to superior CPU with data types and structures is standardized in accordance with IEC 60870-5.
SAS System comprises of main & redundant servers. SICAM SCC used for data acquisition from gateway. The functionality of the HMI System includes collection of data available from the gateway and shows the same for monitoring by the operator. The offered HMI system provides real time, high resolution and interactive graphics display of the collected information, real-time and historical trending of substation parameters, user selectable type reports of historical information stored in high data integrity Data Base…etc.
An Engineering workstation (laptop) provided on the same machine for carrying out configuration and modifications of SAS screens. The laptop computer is equipped with engineering software – Toolbox II for the gateway. It is also possible to carry out on-line diagnostics of the gateway using the Toolbox II on the Ethernet LAN.
SICAM SCC allows the following standard and multiple secured functions in order to solve the automation
Tasks of your system,
* Pictures / Visualization
* Acknowledgeable State List (ASL)
* Chronological Event List (CEL)
* Telecontrol connection
The scalability is also a principle for the functionality of the system, which can be extended with high performance applications at any time, like switching sequences, interlocking, trends, etc
The SICAM SCC doesn’t consider the individual data-points, but the technological objects. That is the basic principle for the picture and data modeling, because a considerable simplification of the project’s planning procedures is thereby achieved and a repetition effect is reached through the use of the predefined models.
or alarm text is inserted as blue line with black lettering instead of the alarm information line. This information must be acknowledged like external alarms.
This picture displays the Alarm list with the signal name with occurred time, cleared time & acknowledged time. We have the option of giving the print command & option of filtering the alarm according to the trips,warnings etc.
Here in Alarm screen the option Delete is to delete any alarm, Acknowledge page is to acknowledge the alarms present on the particular page, Acknowledge all is to acknowledge all alarms. And one very important option present here is ‘Filter’ it is used to see and print the alarms of particular time.
This picture displays the action preformed in the SICAM SCC HMI screen with the signal name & the time stamp with the text saying the action preformed. We have the option of giving the print command & option of filtering the event according to the trips, warnings etc.
Here in this screen two main option are present sort and filter. Sort option is only to arrange time present in event list i.e. the latest alarm should be on the top of the list or the bottom of the list. There is another option which is filter; it is used to see particular time events, group events, class events.
This picture displays the report (Analog values such as current, voltage etc) of each feeder at every hour with the time stamp.