Testing and validation of the ACCESS system

With the increasing penetration of distributed renewable generation being connected, a number of solutions have been developed to avoid network overloads. A number of the already implemented schemes are based on generation curtailment during times of high generation and low demand. The ACCESS (Assisting Communities to Connect to Electric Sustainable Sources) system implements a more sophisticated predictive based solution. In the ACCESS system the generation resource and electrical demand is predicted and the storage heating resource is managed, providing a demand side management instead of a generation curtailment solution. The ACCESS system was installed, tested and demonstrated in the Power Network Demonstration Centre (PNDC), a research facility that enables realistic testing of novel hardware and network operation schemes in a controlled environment, in 2015. Following the testing at the PNDC, the ACCESS system was deployed in the Isle of Mull, in 2016. This paper reports on the outcome of the testing of the demand response features of the ACCESS system at the PNDC prior to its deployment on the Isle of Mull. This paper reports on: the different components of the system in detail (i.e. what it is designed to do and why); the test regime undertaken at the PNDC; the results of the testing (i.e. how effectively it achieves its design objectives); and the updates to the ACCESS system based on the testing with regards to the solutions employed and the benefits achieved

Incorporating practice theory in sub-profile models for short term aggregated residential load forecasting

Aspirations of grid independence could be achieved by residential power systems connected only to small highly variable loads, if overall demand on the network can be accurately anticipated. Absence of the diversity found on networks with larger load cohorts or consistent industrial customers, makes such overall load profiles difficult to anticipate on even a short term basis. Here, existing forecasting techniques are employed alongside enhanced classification/clustering models in proposed methods for forecasting demand in a bottom up manner. A Markov Chain based sampling technique derived from Practice Theory of human behavior is proposed as a means of providing a forecast with low computational effort and reduced historical data requirements. The modeling approach proposed does not require seasonal adjustments or environmental data. Forecast and actual demand for a cohort of residential loads over a 5 month period are used to evaluate a number of models as well as demonstrate a significant performance improvement if utilized in an ensemble forecast

Multi-layered simulation platform for future worlds distribution system scenarios

With the current Distribution System Operator (DSO) transition, DSOs are looking for novel cost-effective solutions to manage distribution networks. To avoid operational failures these solutions must be evaluated in a realistic end to end test environment prior to deployment. To meet this requirement PNDC is presently developing a platform that integrates solutions for power system analysis, market modelling, and real-time simulation. This multi-layered simulation platform will be used to investigate the impact of different DSO operational scenarios (e.g. flexibility procurement, communication interfaces, and vendor provided solutions). To develop the case study presented in this paper aspects of the Open Networks ‘Future Worlds’ were utilised. The ‘Future Worlds’ were developed by the UK Energy Networks Association and represent potential scenarios for the UK future electricity industry structure. This paper presents a case study using the PNDC platform. This case study reflects ‘Future World’ A and simulates an enforced power exchange profile at a grid supply point. In the case study a controllable demand is simulated in real-time and interfaces with power flow analysis and an optimal flexibility procurement algorithm. The case study demonstrates the capability of the multi-layered platform to manage network limitations by procuring flexibility services within a simulated distribution network

Evolution of electricity distribution control room data streams - UK case study

The move towards 'Net Zero', the balance of greenhouse gas emissions produced and removed from the atmosphere, is increasing the complexity of managing distribution networks, with more deployments of low carbon technologies, new markets for flexibility services, and greater monitoring and visibility of the network itself. This has driven the UK's Distribution Network Operators who manage the network, to evolve towards becoming Distribution System Operators, taking on a role more akin to the traditionally more complex Transmission System Operator. In parallel with this development, the data streams utilised by the distribution network control room have also evolved. This paper sets out this evolution by detailing the existing data streams within a typical distribution control room, and how these data streams will need to evolve, as well what new sources of data a future control room will need to accommodate, and finally by identifying novel ways that that value can be created from this data through the use of new 'smart' tools

New methods for protection of future power networks incorporating high penetrations of distributed generation

Strathclyde theses - ask staff. Thesis no. : T13469Due to initiatives such as the EU (European Union) 2020 target of 20% of final energy consumption from renewable sources [1], and a target to reduce greenhouse gases from energy production by 80-95% by 2050 [2], the number of renewable generators being connected to power systems is increasing. Many modern renewable generators are inverter-interfaced [3] and many of these are being connected at the distribution level within power systems. This increase in generation at this level of the system can affect the operation of network protection, and with the continuing increase in generation, the impact on protection operation is expected to grow. In this thesis, the growing impact of inverter-interfaced generation on distribution network protection is investigated. Initially, protection problems resulting from increasing DG (Distributed Generation) penetration are investigated and the work of others in this domain is reviewed. A description of the development of an empirical model of an inverter, incorporating fault behaviour, is presented. The model is based on observations of laboratory testing and is developed to accurately model inverter fault behaviour. Three problems are subsequently considered and evaluated using simulation: protection "blinding", loss of protection coordination and sympathetic tripping. Sympathetic tripping is found to be the most 'imminent' problem and a comprehensive simulation based investigation is undertaken to evaluate the extent of sympathetic tripping for typical penetrations of distributed generation. In the latter sections of the thesis, a number of potential solutions are evaluated to ascertain their effectiveness in reducing or preventing the occurrence of protection problems such as sympathetic tripping. Firstly, it is demonstrated that sympathetic tripping can be avoided in most circumstances by modifying the settings specified in the UK Energy Networks Association's G59/2 recommendation. Secondly, the development and operation of an optimisation based technique is described - this can significantly improve the speed of protection operation and thus avoid the occurrence of sympathetic tripping; improvements in protection speed of up to 42 % are achieved with this method. Finally, a communication based blocking scheme is described which employs IP/MPLS (Internet Protocol Multiprotocol Label Switching) communication technology. The operation of this scheme is demonstrated via laboratory testing and it is shown that the selected technology may be effective when adopted within this blocking scheme. The thesis concludes with an overview of future work that is required to further advance the concepts demonstrated.Due to initiatives such as the EU (European Union) 2020 target of 20% of final energy consumption from renewable sources [1], and a target to reduce greenhouse gases from energy production by 80-95% by 2050 [2], the number of renewable generators being connected to power systems is increasing. Many modern renewable generators are inverter-interfaced [3] and many of these are being connected at the distribution level within power systems. This increase in generation at this level of the system can affect the operation of network protection, and with the continuing increase in generation, the impact on protection operation is expected to grow. In this thesis, the growing impact of inverter-interfaced generation on distribution network protection is investigated. Initially, protection problems resulting from increasing DG (Distributed Generation) penetration are investigated and the work of others in this domain is reviewed. A description of the development of an empirical model of an inverter, incorporating fault behaviour, is presented. The model is based on observations of laboratory testing and is developed to accurately model inverter fault behaviour. Three problems are subsequently considered and evaluated using simulation: protection "blinding", loss of protection coordination and sympathetic tripping. Sympathetic tripping is found to be the most 'imminent' problem and a comprehensive simulation based investigation is undertaken to evaluate the extent of sympathetic tripping for typical penetrations of distributed generation. In the latter sections of the thesis, a number of potential solutions are evaluated to ascertain their effectiveness in reducing or preventing the occurrence of protection problems such as sympathetic tripping. Firstly, it is demonstrated that sympathetic tripping can be avoided in most circumstances by modifying the settings specified in the UK Energy Networks Association's G59/2 recommendation. Secondly, the development and operation of an optimisation based technique is described - this can significantly improve the speed of protection operation and thus avoid the occurrence of sympathetic tripping; improvements in protection speed of up to 42 % are achieved with this method. Finally, a communication based blocking scheme is described which employs IP/MPLS (Internet Protocol Multiprotocol Label Switching) communication technology. The operation of this scheme is demonstrated via laboratory testing and it is shown that the selected technology may be effective when adopted within this blocking scheme. The thesis concludes with an overview of future work that is required to further advance the concepts demonstrated

Investigation of the sympathetic tripping problem in power systems with large penetrations of distributed generation

This study contains an investigation into sympathetic tripping – the undesirable disconnection of distributed generators (DGs) (in accordance with the recently-introduced G83/2 under voltage protection) when a network fault occurs in the vicinity of the DG and is not cleared quickly enough by the network protection (i.e. before the DG's under voltage protection operates). An evaluation of the severity of and proposal of solutions to the problem of sympathetic tripping on a typical UK distribution power network is presented. An inverter model (as the majority of DGs will be inverter-interfaced) that characterises the fault response of the inverter and its associated protection functions has been developed for use in simulation through exhaustive laboratory testing of a commercially-available 3 kW inverter for DG application; the observed responses have been modelled and incorporated in a power system simulation package. It is shown, when using presently-adopted DG interface and network protection settings, that the risk of sympathetic tripping is high in several future scenarios. To mitigate this risk, the impact of modifying network protection settings is evaluated. This study has two key findings – determination of the conditions at which the risk of sympathetic tripping is high and evaluation of a technique to mitigate this risk

Analysis of the sympathetic tripping problem for networks with high penetrations of distributed generation

The amount of Distributed Generation (DG - often from renewable energy sources) connected to the UK power system is increasing. This increase has the potential to affect the reliability of protection system operation (a number of instances of protection maloperation have already been experienced [1]). Issues associated with protection that have previously been considered in the literature include: blinding of protection, false tripping (sympathetic tripping), increased or decreased grid infeed levels, unwanted islanding and failure of auto-reclosers [2, 3]. The main focus of this paper is the protection cascade tripping effect caused by sympathetic undervoltage tripping of DG interface protection for network faults at the distribution level. This paper aims to comprehensively investigate and quantify the conditions at which sympathetic undervoltage tripping occurs

A concept solution architecture for electrical distribution control centres

Established network operator control systems continue to evolve, but are neither homogenous nor necessarily designed to scale with the pace of change required to meet decarbonisation aims. Intrinsic to `smart' and `autonomic' power system concepts is a need for adaptive and accordingly more flexible control philosophies, grounded in reflexive systems able to balance local optima with global conditions. To bridge technological differences between these aspirations and foundational infrastructure in place today, principles and techniques in solution architecture are explored. A solution architecture concept design is presented in this paper, primarily intended as a basis for more detailed design iterations toward vendor- and operator-agnostic control systems, and in support of control system scalability and flexibility. Operator aspirations are ambitious, such that systems risk growing in complexity. This risk and associated mitigations are highlighted and incorporated within the proposed design

Presentation_1_Myeloid- and epithelial-derived RELMα contribute to tissue repair following lung helminth infection.pptx

Soil-transmitted helminth (STH) infections impact billions of individuals globally; however, there is a need to clarify the long-term impacts of these infections on pulmonary health owing to their transient migration and subsequent damage to the lungs. In mouse models of these infections using Nippostrongylus brasiliensis, lung pathology persists at later time points post single infection. These studies also indicate the persistent transcriptional expression of resistin-like molecule α (RELMα), an immunomodulatory protein induced in type 2 immunity and alternatively activated macrophages. Using constitutive and tamoxifen-inducible cell-specific RELMα knockout mouse strains, we identified that epithelial- and myeloid-derived RELMα protein remained elevated at 30 days post infection and altered the immune cell signature and gene expression in lung compartments. Histopathological assessment of alveolar damage revealed a role for RELMα in tissue repair, suggesting the importance of sustained RELMα expression for lung recovery from helminth infection. Acellular three-dimensional (3D) lung scaffolds were prepared from the lungs of wild-type (WT), RELMα KO-naive, or 30 days post N. brasiliensis-infected mice to assess their ability to support epithelial cell growth. N. brasiliensis infection significantly altered the scaffold and impaired epithelial cell growth and metabolic activity, especially in the RELMα KO scaffolds. These findings underscore a need to identify the long-term impacts of helminth infection on human pulmonary disease, particularly as alveolar destruction can develop into chronic obstructive pulmonary disease (COPD), which remains among the top global causes of death. Translation of these findings to human protein resistin, with sequence homology to RELMα therapeutic opportunities in lung repair.</p

Cardiac pacing in patients with a cervical spinal cord injury

Study design: Retrospective medical record review. Objectives: To compare patients, admitted to an intensive care unit (ICU) with an acute cervical spinal cord injury (SCI) and documented motor deficit, who did, with those who did not, require a cardiac pacemaker. Setting: South Australian Tertiary Referral Intensive Care and Spinal Injury Unit. Methods: Retrospective medical record review and data set linkage. Results: From 1995 to 2007, 465 patients sustained a cervical SCI. Of these, 30 (6.5%) were admitted to ICU with a clinically assessable motor deficit and 3 (0.6% of all patients, or 10% of those admitted to ICU) required a cardiac pacemaker. All three patients had a cervical SCI, C5 (American Spinal Injury Association A) tetraplegia, and required invasive mechanical respiratory and inotropic support and a tracheostomy for weaning. Two patients (66%) were discharged alive to rehabilitation. Patients requiring a pacemaker had bradycardic episodes over a longer period (11 vs 4 days, P¼0.01), a trend towards a later onset of bradycardia (8 vs 1.5 days, P¼0.05) and a longer ICU length of stay (37 vs 10 days, P¼0.02). Conclusion: Patients with a cervical SCI requiring a cardiac pacemaker are characterized by a higher level of SCI injury and motor loss, require mechanical respiratory and inotropic support, a tracheostomy to wean, and bradycardic episodes of a later onset and over a longer period of time. These findings suggest that such patients should be managed at hospitals with specialized acute spinal injury, intensive care and cardiac pacemaker services.P Rangappa, J Jeyadoss, A Flabouris, JM Clark and R Marshal