55 research outputs found
An open platform for rapid-prototyping protection and control schemes with IEC 61850
Communications is becoming increasingly important to the operation of protection and control schemes. Although offering many benefits, using standards-based communications, particularly IEC 61850, in the course of the research and development of novel schemes can be complex. This paper describes an open-source platform which enables the rapid prototyping of communications-enhanced schemes. The platform automatically generates the data model and communications code required for an intelligent electronic device to implement a publisher-subscriber generic object-oriented substation event and sampled-value messaging. The generated code is tailored to a particular system configuration description (SCD) file, and is therefore extremely efficient at runtime. It is shown here how a model-centric tool, such as the open-source Eclipse Modeling Framework, can be used to manage the complexity of the IEC 61850 standard, by providing a framework for validating SCD files and by automating parts of the code generation process. The flexibility and convenience of the platform are demonstrated through a prototype of a real-time, fast-acting load-shedding scheme for a low-voltage microgrid network. The platform is the first open-source implementation of IEC 61850 which is suitable for real-time applications, such as protection, and is therefore readily available for research and education
Demonstration of adaptive overcurrent protection using IEC 61850 communications
This paper contains a description of an adaptive protection scheme that has been implemented and demonstrated in a hardware in the loop simulation environment using commercially available protection hardware and IEC 61850 communications.The implementation is based on an actual 11kV system which includes distributed generation and network automation. IEC 61850 communications offers several benefits for the implementation of adaptive protection, but also presents some limitations which are discussed in the paper. An alternative approach to overcome a number of the limitations is also presented
New methodology for on-site measurement of Voltage Transformer magnitude and phase ratio as a function of frequency
Inductive Voltage Transformers are commonplace in low and medium voltage power distribution networks and are important for network monitoring and protection. Their performance at frequencies above 50Hz, defined as maintaining transformer ratio and input/output phase relationship, is often completely unknown. It is also a challenge to remove VTs from existing installation points to test thoroughly for VT ratio and phase frequency response using the standard swept-sine variable frequency testing. To meet this challenge, the Power Networks Demonstration Centre (PNDC) has developed a technique which relies on a harmonic analysis of the relationship between the transformer input and output. In laboratory testing it has a speed and safety advantage over conventional techniques, while in the future it may allow comparison with known levels of harmonics distortion on the distribution network to calculate the performance at higher frequencies of VTs in-situ
The reliability and optimal data usage of BGAN satellite communications for remote outstations
Telecommunications are a crucial element of smart grid technologies. Utility communication systems need to combine cost effectiveness with the need for high reliability. Due to its wide geographic coverage, satellite communication can be an appropriate alternative for power system automation in order to reach remote substations. This paper presents the experimental testing of Broadband Global Area Networks (BGAN) M2M technology between the supervisory control and data acquisition (SCADA) system running a primary front end processor (FEP) and the reclosers. Hardware test results for a number of different scenarios are discussed, compared and validated. The challenges for keeping the polls reliability at highest levels are also discussed
An adaptive overcurrent protection scheme for distribution networks
Distribution networks are evolving toward the vision of smart grids, with increasing penetration of distributed generation (DG), introduction of active network management (ANM), and potentially islanded modes of operation. These changes affect fault levels and fault current paths and have been demonstrated to compromise the correct operation of the overcurrent protection system. This paper presents an adaptive overcurrent protection system which automatically amends the protection settings of all overcurrent relays in response to the impact of DG, ANM, and islanding operation. The scheme has been developed using commercially available protection devices, employs IEC61850-based communications, and has been demonstrated and tested using a hardware-in-the-loop laboratory facility. A systematic comparison of the performance of the proposed adaptive scheme alongside that of a conventional overcurrent scheme is presented. This comparison quantifies the decrease in false operations and the reduction of mean operating time that the adaptive system offers
Medium voltage fault location using distributed LV measurements
An MV fault location technique based exclusively on low voltage measurements in the distribution network is presented in this paper. The technique is based on sequence component analysis of the voltage measurements in order to characterise the LV voltage during MV faults. The accuracy of the technique is evaluated using a DigSILENT PowerFactory model where various fault conditions have been studied including the impact of distributed generation connection on the network voltage profile. The model represents the Power Networks Demonstration Centre’s (PNDC) MV and LV test network. This is to facilitate the validation of the model in the future implementing physical fault testing and measurements using the PNDC network
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
International White Book on DER Protection : Review and Testing Procedures
This white book provides an insight into the issues surrounding the impact of increasing levels of DER on the generator and network protection and the resulting necessary improvements in protection testing practices. Particular focus is placed on ever increasing inverter-interfaced DER installations and the challenges of utility network integration. This white book should also serve as a starting point for specifying DER protection testing requirements and procedures. A comprehensive review of international DER protection practices, standards and recommendations is presented. This is accompanied by the identifi cation of the main performance challenges related to these protection schemes under varied network operational conditions and the nature of DER generator and interface technologies. Emphasis is placed on the importance of dynamic testing that can only be delivered through laboratory-based platforms such as real-time simulators, integrated substation automation infrastructure and fl exible, inverter-equipped testing microgrids. To this end, the combination of fl exible network operation and new DER technologies underlines the importance of utilising the laboratory testing facilities available within the DERlab Network of Excellence. This not only informs the shaping of new protection testing and network integration practices by end users but also enables the process of de-risking new DER protection technologies. In order to support the issues discussed in the white paper, a comparative case study between UK and German DER protection and scheme testing practices is presented. This also highlights the level of complexity associated with standardisation and approval mechanisms adopted by different countries
A model-based analysis method for evaluating the grid impact of EV and high harmonic content sources
The impact on the distribution grid when Electric Vehicles are connected is an im-portant technical question in the development of new smart grids. This paper looks in detail at the predictive capability of a model, calculating harmonic voltage and current levels, in the situation where an electric vehicle is being charged by an in-ductive charging plate which acts as a substantial source of harmonic distortion. The method described in this paper models distortion at the LV side of the distribution grid by reconstructing the HV harmonic distortion levels seen at a typical LV sub-station. Additional LV connected harmonic-rich current sources can then be added, allowing a quantitative analysis of the impact of such sources on the distribution grid in terms of measurable harmonics magnitude and phase angle with respect to the fundamental
Dynamic model of commercially available inverters with validation against hardware testing
The increasing penetration of photovoltaics (PV) in the bulk power system has led to the growing need for better understanding the behavior of PV inverters during grid disturbances. A configurable dynamic model is presented in this paper emulating the behavior of a Low Voltage (LV) connected off-the-shelf PV inverter during faults and voltage dips. The model has been developed and validated against the results acquired throughout the empirical characterization of the real inverter. The physical testing of the Device Under Test (DUT) was performed at the Power Networks Demonstration Centre (PNDC), where the required network conditions were applied at the output of the inverter using a Real Time Digital Simulator (RTDS). Further simulations, conducted with the aid of the developed model, aim to reflect a distribution network dominated by inverter connected generation under a number of imposed fault scenarios
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