Case Studies

Integrated SCADA For Electricity Distribution Network

5 July 2017

With 30 million passengers per annum, and operating at its full capacity, Bangkok’s current International Airport, Don Muang, is the busiest airport in South East Asia. Construction on the Second Bangkok International Airport started in January 2002, with the airport scheduled to open in the autumn of 2005.

The new airport’s name, is Suvarnabhumi (pronounced soo‐wan‐na‐poom), which in Thai means ‘golden peninsula’ or ‘golden land’.  Once in operation, it will become Bangkok’s only International Airport, with the present airport, Don Muang, only used for domestic flights.  It is intended that this new airport would act as the aviation hub for South East Asia.

Situated in around 8,000 acres of land east of the city, Suvarnabhumi International Airport is 25km from downtown Bangkok.  The passenger terminal building is a single structure building covering over half a million square metres (world’s largest single building).  The roof trellis is also the largest of its kind. The cargo terminal covers an area of nearly 200,000 square metres.  With a height of 132 metres the airport boasts the tallest control tower in the world.  In its first phase the airport will have two parallel runways each 60m wide and around 4km in length, with over 2km separation.  Two parallel taxiways allow simultaneous landing and take‐off.

At opening day Suvarnabhumi will have an annual passenger capacity of 45 million, and a cargo capacity of 3 million metric tonnes per year, with up to 76 flight operations per hour.  The airport ‘opening day’ cost is estimated to be around 155 billion baht (approximately 4 billion US$).

At its projected fully developed phase (by 2010), the airport will include two passenger terminals, and two additional runways.  The projected annual passenger capacity is 100 million, with a cargo capacity of nearly  6.5 million metric tonnes per year. The number of flight operations would increase to a projected 112 per hour. As a major regional economy Thailand is a frequent and popular travel destination for both business travellers and tourists alike.  Furthermore with its strategic location it acts as a major travel hub for passengers from all around the world.

The Challenge

Clearly the ‘twenty four‐seven’ round the clock running of an airport of such a size and national, regional and international importance requires precision operation and constant availability of essential services, of which the reliability and continuity of the electricity supply is paramount.  The airport receives electric power from 115kV power lines supplied by the etropolitan Electricity Authority of Thailand (MEA), who is the authority responsible for electricity distribution in the metropolis of Bangkok.  At the airport, through its main transformer substation this HV (High Voltage) supply is stepped down to 24kV (Medium Voltage – MV) and distributed to over 60 MV substations strategically located across the airport.  At each MV substation the electric power is further stepped down to 415V (Low Voltage – LV) and fed to the various users / buildings.  A number of Diesel generators are provided for emergency backup power in case of loss of electric power from the MEA supply.

As with any distribution network, supplies are routed through strategic redundant circuits to ensure supply network resilience and continuity.  Some 300 circuit breakers are used on the HV and MV distribution networks.  The Supervisory Control And Data Acquisition (SCADA) system monitors and controls the circuit breakers and other electricity distribution plant (e.g. transformers, diesel generators, utility tunnel LV distribution, etc) across the airport.  The system thus provides the airport authority with the necessary means for the proper operation and control of the electricity distribution network.

The SCADA system requirements reflected those of the supply network itself in reliability and resilience, with relevant functionality so that operators could receive reliable information quickly and easily, and could act and obtain responses speedily and reliably.  The system was thus required to include:

• In‐built fall‐back / redundancy in all main areas including the communications infrastructure.
• The equipment / system offered should be in use and proven for operation in electric utility applications, and the hostile electrical / magnetic environments which are characteristics of such an application.
• The equipment / system should be extremely reliable, with high availability rates.
• Fully integrated with the switchgear protection equipment.
• Feature‐rich Human Machine Interface (HMI) functionality with a high level of operator interaction, including the use of dynamic colouring depicting the various states of the distribution network.
• Automation capabilities including interlocking and inter-tripping functions.
• The main Master Station / Bay Terminal communications media were to be over redundant and resilient fibre optic cables, with TETRA Trunk Radio as a ‘third’ backup bearer.
• Expandable for integration with other airport systems such as the Airport Information and Management System (AIMS).
• With the airport expansion phases in mind the system offered should be flexible, configurable, and offer ‘future proofing’.

The Solution

Remsdaq’s local business partner, Precise International Corporation (PCI), offered Remsdaq’s Celeste SCADA Master and Remsdaq’s Callisto^IES Bay Terminal Unit for this mission critical system, and was awarded the SCADA contract for MV distribution as well as for the Main Transformer substation.

Both Callisto^IES and Celeste Master are in extensive use in electricity projects with MEA and PEA in Thailand.  Celeste is a feature‐rich SCADA Master / HMI application software suite which functions on IBM and compatible PCs under Windows operating system.  It is available as standalone or networked, in standard and redundant configurations.

Callisto^IES is Remsdaq’s state‐of‐the‐art Bay Terminal Unit, with advanced functions specifically developed and deployed in electric utility applications.  Some of the special features of Callisto^IES include:

• Fully flexible and user configurable modular product, suitable for both distributed and concentrated applications.  The unit is totally scalable which allows the user to employ the same module types for applications ranging from a few input / output     (I/O) quantities up to thousands.
• The  processor modules can be networked on a resilient deterministic LAN (ArcNet) physically connected via easily installed plastic or hard clad silica (HCS) fibre optic cable, which is thus totally immune to electromagnetic interference. The deterministic LAN allows the unit to time tag events to 1ms resolution across all its nodes.
• Intelligent Bay Terminal Unit with total flexibility, allowing user defined automation and logic functions to be easily created & programmed by the client and downloaded to the unit for ‘real‐time’ execution.
• Advanced transducerless AC analogue option, which provides the ability to directly connect to measurement PTs and CTs without the need  of using conventional transducers.
• Callisto^IES is available in both standard and redundant server configurations, and can communicate to multiple masters using single or redundant bearer arrangements.
• Communications between the Celeste Master stations and the Callisto^IES units on this project uses the industry standard DNP3.0 protocol, which also makes use of the special provisions within the protocol for additional facilities such as file transfers. This allows remote download of  configuration and automation functions (including application software) directly from the Celeste master stations. This is additional to being able to perform such downloads locally at the Bay Terminal.

In addition to the above, using a rich library of proprietary and industry standard protocols, Callisto^IES can communicate with a variety of protection relays and Intelligent Electronic Devices (IEDs).  For this project the VAMP 230 protection relays were selected.  For each GIS and AIS circuit breaker a Callisto^IES processing node and VAMP 230 relay were used in a closely coupled  Integrated Protection &  Control Bay  Unit (IPCBU) arrangement using serial communications.  Not only was this link used for real‐time data transfer, it also allowed the setting and download of relay parameters and upload of relay fault data directly from the VAMP configuration software operating from the Celeste SCADA terminals.

This arrangement provided a fully integrated protection and control function and yet allowed the Callisto^IES and the VAMP units to retain their autonomous functions under fall ‐back conditions.  At each breaker the small size of these units allowed them to be installed in the switchgear cabinet.  This resulted in a fully compact integrated switchgear arrangement, with the added benefits of simplified and cost effective installation.

This also allowed each switchgear unit to be fully commissioned and tested as a standalone unit together with its IPCBU prior to integration into the whole system, thus providing savings in both cost and project implementation program.

The diagram shows the architecture of the SCADA system.  The system for the Main Transformer Station (MTS) was implemented around a year before the
MV distribution system.

The two systems were integrated seamlessly during the implementation of the MV distribution phase The MTS system consists of Remsdaq’s Celeste master station in redundant configuration.  Callisto^IES processing nodes are installed at a number of locations for the monitoring and control of plant I/O data and communicate with the Celeste master over a pair of redundant Callisto^IES servers.

The master station for the MV distribution system also uses Remsdaq’s Celeste SCADA master operating in redundant configuration and situated in two control centres.  The Ethernet LAN between the redundant masters is provided via duplicated fibre optic links.  The IPCBUs for the MV system are located at the MV substations.  These units are strategically grouped (the
grouping coincides with that of the MV distribution network itself), and are connected to the redundant Celeste master station over a pair of fibre optic communications cables each arranged in a loop configuration, using Callisto^IES servers operating in redundant mode.  This configuration results in an extremely resilient arrangement where communication with the IPCBU can still be made even with up to four independent cable / equipment failures.

The 60+ MV IPCBUs and those for the GIS units on the current system reside on a total of 12 such loops (connected to the master stations via a total of around 300km of fibre optic cable), with the capability to add further loops in the future.

Business Benefits

• The Remsdaq Celeste /Callisto^IES SCADA system and VAMP protection relays provided the client with an advanced technology, highly reliable, resilient and yet cost‐effective solution.
• System reliability, in‐built redundancies at key elements, and fall‐back arrangements, ensure high equipment availability fitting of  such a mission  critical application, where security and safety at all times is of paramount importance.
• Use of fibre optic technology ensures communications and data security and immunity to electromagnetic disturbances present due to power distribution equipment / cables, and airport communications and radar equipment.
• The SCADA system solution afforded a fully integrated arrangement using the same equipment types for the Main Transformer and MV Distribution scheme; thus resulting in common spares holdings, standardised training and maintenance activities, etc.
• The use of Callisto^IES and VAMP IPCBUs and their build into the switchgear cabinets provides a highly integrated switchgear protection and control system with the added benefits of fall‐back.  This design allowed each switchgear panel to be treated as a self ‐contained unit, resulting in an efficient installation and commissioning program.  This further contributed to overall savings in cost and project implementation timescales.
• The flexibility and configurability of the Celeste master and Callisto^IES units and the modularity of Callisto^IES coupled with the future proofing of the products allow the client to easily and cost effectively undertake phased expansion of the system in line with the airport expansion programs.
• Use of the advanced transducerless AC option allows the client to take advantage of the extensive features & facilities of this option.  For example with the direct connection to the PTs and CTs and the direct sampling of the AC voltage and current waveforms, at the rate of 128 samples per cycle, Callisto^IES will measure the RMS values of voltage and current to 0.1% accuracy.  This would allow the unit to also calculate other electric power data such as real and reactive power (kW, kVAR) and VA, kWh and kVARh, power factor, frequency, harmonics, THD, etc., per phase and total.  In particular, calculated values, such as kwh, can be used as a means of measuring the power consumed by different users of the distribution network within the airport.
• Capabilities / potential for integration with other airport systems.