Arab Gas Pipeline
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Nata : National Advanced Transmission & Automation Centre
Where failure fears to tread
Nata is the core and crux of our control over the grid. It is our smart choice to put the best innovation to work in the national gas grid through a group of integrated systems providing perfect professional performance for safe gas supply .Gasco has built Nata from bricks to clicks to maintain utmost control of the grid through the use of the following technologies, systems and programs:
• Supervisory control and Data Acquisition Systems (SCADA)
• Gas Grid Analysis
• Gas grid upgrading, maintenance and development systems
Supervisory Control and Data Acquisition system
A tool to match our performance, the SCADA system is a highly sophisticated integrated system bringing the fields to the field of vision while masterminding co-ordination and control of gas transmission & distribution, analysis for failure or leakage via an advanced bundle of software applications making remote processes visible to everyone from control room operators to contingency management team, and decision support systems. The SCADA system comprises the following:
1. The remote terminal units (RTUs)
Providing direct and timely information, the remote terminal units (RTUs) are responsible for collecting data from field devices at sites of the company. Control commands to different devices, such as valves with actuators, can be issued via RTUs.
2. Control Centers
The control centers work 24 hrs a day, 7 days a week, based on sophisticated emergency scenarios. It represents the master terminal unit which is composed of hardware components and software components integrated to comprise a full control system. Hardware components include Real time servers, historical servers, operators workstations, storage drives and media devices, Computer Networks and communication channels. Software components include servers and workstations operating systems real time and historical database systems, master terminal unit polling routines (MTU) polling routines which poll RTUs to get gas stations data.
• Great Control Center
The National Advanced Transmission and Automation (NATA) is the Main Control Center It represents the global scope for the operation of the National Gas Grid.
• Local Control & monitoring Centers
There are 4 local control centers in Cairo, Alex, Suez, in addition to 8 monitoring centers in port said ,el-aresh , East of Alex,10th of Ramadan city, Sharqawya, Damietta, Talkha ,and East of Alex (El-Mahmoudia) Three control centers will be added at Sharm-Elsheikh, Minea city & Aswan ( under construction ).
• Emergency Control Center
The system is designed to allow one of the local control centers (Shabshir) to work as emergency control centre in case of failure.
3. Telecommunication network
The system is supported by a robust telecommunication network comprising primary digital microwave network, secondary digital microwave network, fiber optics network, and digital land mobile trucking network. The primary digital microwave network working in the 7 Giga Hz frequency band and is used to connect the main control center to the local control centers. The Secondary telecommunication network, is where the Real-time data of control sites is transmitted to the local control centers by using 4 secondary digital microwave channels for each control center within a frequency of 2.4 Giga Hz. These networks also provide voice communication between all sites. Fiber optics system is installed with most recent pipelines to provide telecommunications services over that pipeline such as Amreya / Dahshour and Quantara / Eyon Moussa
4. Software applications
A number of software applications are applied in system controlling:
SCADA SOFTWARE: is the basic software of control centers it’s a package of software modules responsible for :
1- Gathering stations data
2- Human machine interface (HMI) and supervisory Control
3- Generating alarms after inspecting gathered data.
4- Generating events
5- Historical Database (events, timeline, trends)
7- Synchronization with other control centers
Gas Grid simulation software has two modes of operation,
First mode is connecting to the SCADA providing integrated & leveraged estimated real time data of the whole national gas grid, it is capable of predicting leaks, while providing quantitative and qualitative analysis of the National Gas Grid and its facilities specially valves maintaining utmost control over the grid.
Offline simulation acting as network analysis tool, which helps in handling contingencies while maintaining optimum mode of operation.
5. Network analysis
GASCO achieves its main mission of supplying gas to all consumers through a grid of pipelines with different diameters. In 1997 the length of the national grid was 2800 Km and a capacity of 37 million m3/day. due expansion projects and constructing new pipelines, the national grid has reached 6965 km in length (Trunking pipelines) and a capacity of 205 million m3/day
Database information for all the grid pipelines is used as an input data to the program. The usual approach is to make estimates and closely follow trends in load growth, updating the network at regular intervals to effectively determine the flows and pressures in all pipelines and pipe junctions.
Network analysis, a flexible visualizing tool using the most state-of the art computer software, has the following applications in the national gas grid:
• Analyzing existing loads of the grid and the peak load expected while determining the rate of growth and the positioning of different rate of growth accurately within the network putting the big picture before the eyes of NATA operators.
• Testing the network under specific conditions such as the effect of adding a new load. This will determine whether the existing system is capable of taking the new load and, if not, the extent of additional work required to accommodate it.
• Identification of reinforcement schemes to determine the minimum pressure areas within an existing network and hence the requirement for reinforcement of these areas verifying that load data and load growth rates are accurate and there are no interruptible loads within the system.
• Pressure optimization to minimize the requirement for compression in high pressure pipelines.