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With low voltage (LV) distribution networks increasingly being re-purposed beyond their original design specifications to accommodate low carbon technologies, the ability to accurately calculate their actual spare capacity is critical. Traditionally, within the Great Britain (GB) power system, there has been limited monitoring of LV distribution networks, making this difficult. This paper proposes a method for estimating spare capacity of unmonitored LV networks using demand data from customer Smart Meters. In particular, the proposed method infers existing LV network capacity, as well as losses, across scenarios where only a limited number of customers have Smart Meters installed. Typical daily load profiles across customers with Smart Meters are learned using a Dirichlet sampled Gaussian mixture model (GMM). Learned profiles are then applied to all unmetered customers to estimate network parameters. Method accuracy is assessed by comparing estimations with simulated, fully observed, LV network models. The method is also compared to benchmark models for establishing unobserved demand profiles. Overall, results in the paper show that the proposed method outperforms benchmark models in terms of accurately assessing substation headroom, particularly in scenarios where only 10–50% of customers have Smart Meters installed. [ABSTRACT FROM AUTHOR]

DC technology has gained considerable interest in the medium voltage applications due to the benefits over the AC counterpart. However, to utilize the full capacity of this development, the selection of a suitable power electronic converter topology is a key aspect. From the pool of voltage source converters (VSC's), it is unclear which topology is suitable for multi-megawatt applications at medium voltage dc (MVdc) levels. To address this, the paper proposes a selection guideline based on reliability and optimum redundancy levels of VSCs for MVdc applications. This will be combined with other functional factors such as operational efficiency and return-on-investment. Three candidate multi-level topologies namely three-level neutral point clamped converter (3L-NPC), modular multi-level converter (MMC) and cascaded 3L-NPC (which is being used for the first MVdc link in the U.K.) have been evaluated over two-level-VSC from $\pm$ 10 kV to $\pm$ 50 kV. Results show that with the increase of MVdc voltage level MMC shows better performance whereas at low MVdc voltage levels 3L-NPC is the prominent topology. [ABSTRACT FROM AUTHOR]

This paper presents a comparison of two forms of cable connection of a distant offshore wind farm to a transmission system: AC and HVDC. The requirements of relevant industry standards in Great Britain (GB) that drive a connection design and, hence, its costs are highlighted along with an analysis of the ways in which AC cable connections might be made to comply while facilitating the export of active power. Dynamic studies investigating responses to grid-side short-circuit faults show that, in the particular scenarios studied, an AC connection of a wind farm in place of a large synchronous generator is marginally detrimental while an HVDC connection is beneficial. A comparison of costs shows that the crossover distance at which HVDC is cheaper than AC for wind farms of different sizes occurs at longer distances than have hitherto commonly been assumed, and AC connections benefit from reactive compensation not only at the point of common coupling and wind farm end, but also at the connection midpoint. [ABSTRACT FROM AUTHOR]

Abstract-Partial discharges (PDs) generate wideband radio-frequency interference which can be used for noninvasive monitoring of discharges. This paper presents a novel method based on this principle for PD monitoring of substations. The significant advantage of this method lies in the ability to detect PD sources in energized equipment anywhere within a substation compound during normal operating conditions. The results obtained from the prototypes installed in the U.K. and U.S. substations are reported. Results include correlation with apparent charge and daily recordings obtained before, during, and after the failure of a 132-kV current transformer and 69-ky voltage transformer. [ABSTRACT FROM AUTHOR]

The Under-Frequency Load Shedding (UFLS) scheme is an emergency measure in place to prevent system collapse in the event of a large generation deficit relative to demand at any moment in time. However, the effectiveness of traditional UFLS schemes may be compromised as network power flows change due to the growth of distributed generation (DG) and a reduction in system inertia. This study has shown some of the issues affecting the UFLS protection system with rising installed capacities of DG in the Great Britain power system. Simulation results show how the effectiveness of the scheme is challenged with current and future expected DG installed capacities and the risk of over shedding demand due to the scheme’s current settings is evaluated. Many proposed improvements to traditional load shedding schemes are based on upgrades to network monitoring and communication systems, which are not yet fully available. This study evaluates more readily available solutions, including relocation of under-frequency relays and reducing the time delay of the scheme, which may provide interim improvements to the UFLS scheme, based on a case study in GB. [ABSTRACT FROM AUTHOR]

Distribution companies are increasingly turning to active network management to improve how networks perform with respect to different metrics or objectives. This includes Conservation Voltage Reduction (CVR) that seeks to minimize energy usage of consumers (mostly connected to low voltage, LV, levels) by reducing their supply voltage. However, if medium voltage (MV) levels have to be reduced to achieve CVR, it can negatively affect the energy losses in MV networks. In this study, we explore the potential trade-off that may exist between reducing energy consumption of LV networks and the potential increase in energy losses in MV networks. A Pareto Particle Swarm Optimization (PPSO) is used to actively control voltage devices, including on-load tap changer-fitted LV transformers and MV capacitors. Using three realistically modelled radially operated UK MV/LV networks serving 37,000+ customers (94% residential, 6% commercial and industrial), our results show that a trade-off does exist, but it can be reduced with increasing network control flexibility, particularly with controllable LV transformers. Furthermore, for these networks the reduction in energy consumption due to CVR can be 20 times larger than the increase seen in MV energy losses. These insights are useful for distribution companies in assessing the overall benefits of CVR with active voltage management despite small increases in MV energy losses. [ABSTRACT FROM AUTHOR]

Focuses on electric deregulation in Great Britain, and key issues affecting future communications. Generation of the transmission company, Central Electricity Generating Board; Modernization of communication technology; Introduction of standard performance criteria; distribution of companies in the region.

Presents a proposed communication infrastructure for South Western Electricity PLC, an electric power company in Great Britain. Background information on the company; Information requirements; Scheduling and dispatching generating links in England and Wales; Operation, maintenance and development of the main interconnected transmission system.

In the absence of phase transposition, overhead lines are a major source of unbalance in both currents and voltages on the transmission system. In the England and Wales (E&W) transmission system, the individual circuits are phased such that the average unbalance produced is minimized. The main negative phase-sequence (NPS) voltages on the transmission system arise at loop-in points for generation and load connection under an outage condition of one of the connection circuits and where there is a large NPS voltage induction from the parallel circuit. If not limited, excessive unbalance can cause system incidents and lead to damage of power system equipment. [ABSTRACT FROM AUTHOR]

Studies points to consider in the development of electric utilities networks towards the national information infrastructure in Great Britain. Utility-customer communications; Application of telecommunications and information technologies to the generation, delivery and utilization of electric power.