Caterpillar manufacture a wide range of generators, such as:
The generators are used in diverse applications from standby power for commercial buildings up to prime-power, power stations such as:
Simultaneously, the control system network architecture is optimised. SCADA in power distribution systems may be used for the control of the generators, either individually or as a dispatch-able generation unit.
The electrical protection system is developed from the power system studies and interfaced to the control system and the SCADA.
The power and control systems need to interface with the Caterpillar generators. The generators are delivered as manufactured units from overseas but require installation, testing and commissioning at the project site.
The detailed design for the electrical power and control enables purchasing of the control panels, motor control centres, low voltage switchgear assemblies, medium voltage switchgear assemblies, transformers, cables and switch-rooms, as required by the project.
BESST Engineering is a specialist power and control systems solutions provider for Caterpillar generator applications.
Utility reliability is an important measure of the availability of electrical supply to electrical consumers.
Targets are set for the reliability performance of the utility. The targets are based on measurement of the reliability performance against benchmark values set by the regulating authority. The reliability performance is broken down into areas, substations and feeders.
The utility will identify where the reliability performance is not satisfactory and will develop a strategy and policies to improve the performance. Worst performing feeders are identified and reliability improvement plans developed for each feeder. The plan may involve a combination of capital expenditure and operating or maintenance programmes. There are methods which are used to calculate the economic justification of the reliability improvement. The economic values considered include present worth value, benefit cost ratio and payback. The cost of penalties imposed by the regulator for unsatisfactory performance are also considered.
Utility reliability is measured using industry standard indices. Commonly used indices are:
The calculation of the indices for reliability performance requires the collection and recording of the applicable data. The quality of the data is important for accurate calculation of the indices.
One method which is used to improve the reliability performance is to develop self-healing networks. The concept of the self-healing network is that automation is deployed to allow a portion of the network to recover from an unscheduled outage, while isolating only the circuit associated with the outage. In this way the number of consumers affected can be minimised.
In the same way, self-healing circuits may be used in micro-grids. The development of the self-healing design starts with identifying target reliability indices. The design of the micro-grid can then be modelled for reliability and areas of unsatisfactory performance may be identified. Remedial strategies can be developed and the economic value of the strategies can be estimated.
BESST Engineering is able to model the micro-grid, develop reliability indices and to design reliability improvement strategies, such as self-healing networks. BESST Engineering can assist in the economic valuation of the strategies.
In the early days of electric power the use of DC power was promoted by Edison. The use of AC power was in competition to the use of DC power. AC power prevailed with the invention of the transformer, which allowed power to be carried over large distances. The increased use of AC power has occurred since the 1890s to the present day.
There has been significant technological development of AC systems as a result of research into AC arc faults, AC protection systems and AC fault interruption.
DC power has made a comeback in recent times with the use of power electronics and photovoltaic solar panels. The increased use of DC power has caused a need for DC technology which provides the same protection functions as that used in AC power systems.
A fundamental problem for DC power systems is the detection and interruption of DC arc faults.
DC arc faults pose a significant hazard in photovoltaic solar systems. This is firstly because of the characteristics of the DC arc and secondly because of the difficulty in isolating the fault.
The DC current does not have the zero crossing point characteristic of AC current. Therefore the characteristics of the DC arc fault are different to those of an AC arc fault. The lack of a zero crossing makes it is more difficult to interrupt the DC arc fault.
If a DC arc fault occurs, the next problem is how to detect the presence of the arc fault. In applications such as variable frequency drives, the DC arc fault may occur together with an AC arc fault. The AC fault level may be limited by the use of reactors or earthing transformers. However, these devices may not be suitable for the limitation of DC fault currents.
AC earth leakage protection relays may be used to detect an AC earth fault. The detection of a DC earth fault requires DC earth leakage protection relays.
The photovoltaic solar panel acts as a generator and an energy source. Exposure of the solar panel to sunlight produces a DC output voltage. The solar panel is switched off when the sunlight is removed.
The solar panel may be connected with many other panels in series into a solar array to produce a suitable DC output voltage. The presence of a DC arc fault either inside the individual panel or within the array can present a series hazard. The risk to the array and to the whole photovoltaic system from the DC arc fault depends on the fault scenario.
BESST is able to provide DC power system load flow and protection studies for solar power generation and power electronics applications.
There is generally an increased awareness of the importance of work place health and safety. From an electrical perspective, this applies to both electrical and non-electrical workers.
While electrical safety depends upon many things, such as safe operational and maintenance procedures, there is an important contribution that can be made during the design phase of a new project.
The first step is to include electrical safety at an early stage in the high level design documents for the project. This may be achieved by having electrical safety quantified within the design goals, design reviews and evaluation criteria for the electrical system.
Basically the electrical risks need to be identified during the design stage. Action can be taken during this stage to implement engineered control of the risks. The safety criteria can be determined. The applicable legal requirements and safety related standards can be identified. A procedure for standardising solutions to electrical risks can be prepared. References can be made to the appropriate work place health and safety guidelines, safety codes and industry practices.
It is too late once the design is complete and the project moves to construction. A rigorous safety audit of the proposed design can be used to confirm the corrective measures. The whole process should be documented and tackled with appropriate due diligence.
Safety risk assessment can be included in the design review procedures. The aim is either minimise or eliminate the risk through engineering.
Action to be taken during the electrical design includes:
BESST is able to provide assistance in enhancing electrical safety through design. BESST is able to prepare high level documentation, identify electrical risks and determine methods of risk control.
As part of the foundations for a smart grid, the concept and definition of a micro grid has been evolving.
The Micro Grid Institute provides a definition of a micro grid as a small energy system capable of balancing captive supply and demand resources to maintain stable service within a defined boundary.
Further, that micro grids are defined by their function, not by their size and that there a mainly three categories of micro grids:
The isolated islands are used in remote areas as dedicated power generation for a specific application or geographic area. Applications include remote mine sites and townships. The micro grid satisfies the need for electrification. Key requirements are the security of supply, survivability, efficiency and operating costs.
Islandable micro grids are used in either in mission critical applications such as hospitals, data centres or in distributed generation situations where there is a local load. There are coal mines which use gas fuelled generators for both revenue and back-up island operation.
The diverse range of technologies which can be found in micro grids include:
The IEEE 1547 series of standards was developed to provide standards for the interconnecting of distributed resources with electric power systems. The documents provide uniform requirements for the performance, operation, safety, testing and maintenance of the interconnection. The standards apply for the interconnection of 10 MVA or less. A workshop was held in December 2014 to initiate the process of developing the next version of IEEE 1547. One of the questions to be addressed is whether there is a need to expand and include more requirements for islanding (micro grids, Etc.).
In Australia each utility has in-house developed standards for interconnection. There are requirements specified by the Australian Energy Market Operator for systems of 30 MVA or greater, which are connected to the grid.
BESST can provide the power and control system design for micro grid systems, including SCADA networks and system commissioning.
Profibus is a field bus system which was developed in Germany ub rgw `9809a. It is multi-vendor and inter-operable and complies with IEC 61158. .
There is Profibus DP (decentralized peripherals) and Profibus PA (process automation).
Profibus provides a means of automation via de-centralised input / outputs. Compared with traditional, hard-wired systems, the use of Profibus provides:
There are other important benefits for OEMs and automation projects which use Profibus.
The Profibus system is very flexible. It allows the coupling of Profibus DP to Profibus PA to form a combined network.
Profibus PA may be used in hazardous areas in accordance with the FISCO concept (Field Bus Intrinsically Safe Concept). FISCO is defined in AS/NZS 60079.27:2008. It is a global technique for an intrinsically safe field bus. FISCO systems are predominately used in zone 1 and zone 2 locations.
Profibus DP uses an RS485, twisted-pair, shielded bus cable. The cable installation may be tested independent of having a master controller connected. Similarly, the network may be addressed and proven independent of a master controller. Fibre optic cables may be used for where long distances are required or where electrical interference is a problem.
Profibus PA uses a Manchester bus, powered network that provides a field bus solution for process automation systems with field devices such as transmitters, converters, positioners and sensors. It allows the instruments to be configured and monitored via the field bus. Profibus PA was developed in co-operation with the Control and Process Industry (NAMUR), in compliance with the special requirements of this industry.
The Profibus network may have more than one master. The slaves in the network can be independently assigned to a particular master.
This allows the use of PROFIsafe. PROFIsafe is a safety communication technology for distributed automation. It can be used in safety applications up to Safety Integrity Level 3 (SIL) in accordance with IEC 61508 or Category 4 in accordance with EN 954-1. PROFIsafe is a separate layer on top of the fieldbus application layer, to reduce the probability of data transmission errors. PROFIsafe complies with IEC 61784-3-3.
As a field bus system, the reliability of the system is dependent on the quality of the network design, the quality of the installation and the competency of the set-up and commissioning. BESST can provide the system design for Profibus networks and can assist with the installation and commissioning of Profibus networks.
With the emphasis on renewables for electrical power generation, there has been a plethora of proposals on how to achieve up to 100% of the planet’s electrical needs from renewables.
There was well thought out proposal published in the Scientific American which demonstrated how renewable energy production and storage could be used in the United States of America. The proposal was to install approximately 250,000 square miles of photovoltaic panels in the deserts of south western, desert regions. The power generated by the photovoltaic panels was to be distributed by a new transmission grid, to those centres which consumed the power. During the day, the power was to run compressors at the power consumption areas e.g. cities. The air compressors would produce compressed air which would be stored in underground caverns. In the evenings, the compressed air would be mixed with natural gas and used to run gas turbines to produce electricity. The estimated cost was hundreds of billions of dollar and the construction time was decades.
In Europe, there was a proposal to install vast tracts of photovoltaic panels in the Saharan deserts of northern Africa. Undersea transmission lines were to be installed in the Mediterranean Sea to bring the generated power to Europe.
The amount of electrical power generation produced from wind has been increasing significantly. Wind turbines have been increasing in capacity and in the number deployed in each wind farms. The focus has been for offshore wind farms because of the better wind availability. The UK government has recently announced plans to build the largest wind farm in the world. This is the East Anglia One wind farm, off the coast of Suffolk. The plan is to install up to 240 wind turbines, which will generate enough for around 820,000 homes.
In the meantime, there is ITER. What is ITER? ITER is an international collaboration project to demonstrate the feasibility of fusion energy, which could be used as a new source of power. The fusion releases energy which could be used to produce steam for steam turbines to produce electricity. If successful, the fusion power could be a clean, sustainable source of energy.
The research into the possibilities of fusion power began in the 1920s, when it was understood how energy could be produced by combining hydrogen to form helium.
The ITER project is located in France and it is a collaboration between the European Union and six countries – the former Soviet Union, the United States of America, Japan, and the People’s Republic of China, the Republic of Korea and India.
Q symbolises the ratio of the fusion power output to the input power. The scientific goal of the ITER project is to achieve Q>=10. That is, the project would deliver ten times the power it consumes.
It successful, the project would test technologies which could be used to commercialise the use of fusion power. The fusion power station could be located close to where the power is consumed, because it is independent of fossil fuels, wind and solar power.
In the future, it may then be possible to have a stable grid using energy that is clean and sustainable, with a combination of distributed power from renewables and larger, centralised fusion, power plants.
BESST can provide designs for power and control systems, regardless of the source of power generation.
There is currently a great interest in the application of micro-grids to help support the grid, especially for critical loads.
There are research projects in Europe, Japan and the United States of America which are being used to evaluate technologies and learn how to optimise the concept of a micro-grid.
The term “micro-grid” can encompass many derivations depending on the application. For instance, a large facility such as a hospital may operate a micro-grid in order to have security of electrical supply. An off-grid, remote site such as a mining facility may operate a micro-grid as the sole source of power for the facility. Similarly, a ship application may be considered as a special micro-grid for marine applications. Another example is that of a community micro-grid, which may export renewable power into the grid and which has the capability of going “off grid”.
The article in the IEEE SmartGrid publication by Kevin P. Schneider introduces the concept of the Smart Power Infrastructure Demonstration for Energy Reliability and Security (SPIDERS).
There are descriptions of three operational demonstrations of micro-grids. The micro-grid applications are for mission critical, military facilities in the United States of America. The demonstrations are scheduled to finish in 2015.There are high-level requirements:
For each demonstration, an Integrated Assessment Plan (IAP) and a utility assessment report is to be developed. The Integrated Assessment Plan is further divided into six Measures of Effectiveness (MOEs):
Within each of the six measures, there are further Measures of Performance (MOPs) which correlate to specific measurements.
It is interesting to observe the structure of the evaluation process for each demonstration, with four high-level requirements, an Integrated Assessment Plan (IAP), six Measures of Effectiveness (MOEs) and further Measures of Performance.The question is what is the evaluation process which is to be used for your micro-grid application? BESST is able to provide evaluation structures and design the power and control systems for your micro-grid.
The ability to deliver distributed generation to support the grid is rapidly improving as the demand increases.
There is an example of GE delivering 104 MW of distributed generation in a matter of weeks. The generation package comprised four (4) gas turbines, of which two were delivered in 45 days.
The reduced delivery time was achieved using:
The distributed generation, if modular, has the possibility of being re-deployed to another site if the needs change.
The distributed generation may be embedded at the substation level or located at the end user level.
The distributed generation units may be traditional, thermal generators or renewable generators such as wind and solar, or hybrids.
The distributed generation can be used to support specific areas of the grid and to increase the grid security.
In order to deploy the distributed generation, the proper integration of the generation with the grid requires some analysis and design. For example, the distributed generation may need to be dispatched and monitored remotely. This may require integration of the generation control system into a SCADA. The extra generation may increase fault levels at the site, which could impact protection systems. The point of connection for the power circuits, the fuel system, earthing and lightning protection are other areas of consideration.
BESST are able to design the power and control systems for distributed generation, and integrate the generation into the existing power and control systems of the user.
In using the term “gas train”, it is not in reference to the large LNG plants which produce liquefied natural gas (LNG) for export and shipment.
For the purposes of this narrative, the term “gas train” refers to the intake assembly on stationary gas turbines and gas ignition, internal combustion engines. The “gas train” controls the supply of gas to the turbine or engine. Gas trains are also found on burners, boilers, ovens and similar equipment.
What is a gas train? The gas train typically comprises a combination of isolation valve, filter, let-down regulator, over-pressure relief, vents, and shut-off valves. The function of the gas train is to automatically regulate the flow of gas to the turbine or engine and to safely shut off the gas.
In Australia, there are special safety requirements required for stationary, gas fuelled, turbines and engines, which are referred to as “Type B Appliances”. The gas train must meet the requirements for type B approval.
For larger type B appliances, part of the approval process covers the identification and classification of hazardous areas associated with the gas train.
Typical hazardous areas are:
The hazardous areas are assessed and classified in accordance with Australian Standards. Information which needs to be collected for the assessment includes ventilation, properties of the gas, the gas train P&ID, the gas train assembly details and Ex certificates for devices.
Layout and general arrangement drawings are produced which show the proposed location of the gas train in relation to the gas turbine or engine. This allows identification of the electrical equipment which may be within the hazardous area.
The electrical components and installation are designed according to the hazardous area classification.
The completed design forms the basis of the documentation required for approval of the type B appliance by the gas assessor.
BESST has the necessary competency to provide hazardous area assessment and electrical design services, including the assessment of gas trains.