Scada (supervisory Control and Data Acquisition)

                               Executive Summary

The immense blackout in recent years in Pakistan causes many problems in industries and residential areas. To find the cheaper and sustainable means of generating electricity at an affordable price is the main challenge facing the country at the moment. The Siemens is proposing an idea to integrate the renewable power generation, power monitoring and control systems into automated micro-grids (independent grid) at affordable price for the country.          

Aim of this project is to control and manage load of consumers using micro-grid. Micro-grid will be containing different sources such as direct solar without battery, sources from the supplier that can be hydel, thermal or any other. Only dc loads will be used everywhere and these loads will be energized using solar sources. After sunset, load will be shifted to the secondary sources from the supplier. The load parameters will be continuously monitored on SCADA at micro grid or at any other remote station.

In order to excite loads more than the prescribed limit, SCADA (Supervisory Control and Data Acquisition) will notify and transfer that upcoming load to the tertiary supply with the help of PLC (Programmable Logic Controller) by using ATS (Automatic Transfer Switch). Tertiary can be UPS, Generator (depending upon the need).ATS will switch the load between the different sources from micro-grid. A wireless link can be used transfer monitoring and control data to remote SCADA.

Introduction

A micro-grid is basically a small scale power grid that can operate independently. Micro-grid will be relying on a combination of power generation sources depending upon the cost, reliability and availability. SCADA and PLC hardware and software systems will be used to control the integration and management of the micro-grid. Micro-grid integrates existing power generation assets with new or existing renewable power sources and manages energy demands, whether connected or independent of a utility power grid. The priority of disconnecting is variable and can be changed from time to time. The cost involved for restarting a power plant is much more.

The basic idea behind the project is to manage the power in various loads. These loads are models for the different areas of the city. If the load in any area increases then there is a chance that the power station may trip which causes blackout. Hence to avoid this from happening we have proposed a PLC based hardware. When any one load increases from limit, then one of the loads that are connected out of many is disconnected and it will be connected to any secondary or tertiary supply. SCADA will be used for connecting, disconnecting and monitoring the loads in a particular sequence.

Objectives

• Connecting and disconnecting loads will be depending upon the prescribed limit by interfacing current sensor with SCADA.
• Automatic transfer switch for all loads if no primary supply is available.
• Automatic transfer of just upcoming loads to secondary supply if load level increases the limiting value (for minimal energy usage).
• Reducing man power.
• Reduction in chances of error caused by manual operations.
• Supply will be uninterrupted and this whole system will be very fast.
• Automatic monitoring of all load parameters on SCADA.
• Effect of load variations will be monitored with major parameters.
• Load sharing between different consumers.
• Micro-grid has the capability of automatically connecting, disconnecting and operating independently from the main grid.

Market forces

The key factors that are influencing the emergence of micro-grid solutions are the basically exposure of energy infrastructure to cyber-attack, economic analysis, the continuous increasing need for reliable and secure power, growing energy demand.

Cyber security

As the cyber security threats have increased, due to which energy and utilities are highly targets. Factors are:

• Critical infrastructure
• Utilities customer information
• Hacktivists (controversial operations)
• Secure network (military and research labs)

Economic analysis

Government analysis for energy efficiency, electric vehicle infrastructure and renewable power generation they all stimulate investment in advanced energy infrastructure.

Reliable and secure power

Many industrial and commercial environments have a critical need for a constant supply of power and cannot afford blackouts. 

Modern societies are now becoming increasing dependent on secure and reliable electricity supplies to support community prosperity and economic growth.

Growing demand

As the population is growing very rapidly and more electricity is being used per person, increasing stress on the physical grid, congestion and environmental problems. It has become a great challenge to maintain the reliability of the system.  

consumers Benefits

           Reliability

[pic 1]In Pakistan, energy consumer’s expectations for high quality and reliable electricity are getting very high and they don’t even expect to pay a lot. They need the lights to stay on, production lines to keep running and energy costs to be low. Reliability targets are the way to encourage utilities to improve reliability. The micro-grid provides a high quality power, reliable power supply, self-healing power systems, automated control and autonomous systems. The micro-grid is resilient.

Efficiency

The micro-grid is very efficient, peak demand, reducing energy consumption. Such efficiencies can help to delay the construction of new generation plants to meet electricity demand.  A fastest way to impact the energy costs is lowering consumption. To create transparency throughout the system with advanced metering to control savings is the first step. Minimizing transmission and distribution line losses can be done by increasing the amount of on-site generation.

Environmental and conservation benefits