Conversion of HVAC Lines into HVDC in Transmission Expansion Planning

This paper presents a transmission planning methodology that considers the conversion of HVAC transmission lines to HVDC as an alternative of expansion of power systems, as a consequence of restrictions for the construction of new lines. The transmission expansion planning problem formulates an optimization problem that minimizes the total cost that includes the investment cost to convert lines from HVAC to HVDC and possible required reinforcements of the power system prior to the conversion. The costs analysis assesses the impact of the conversion on the reliability because transmission lines are out of service during the conversion work. The presented methodology is applied to a test system considering a planning a horizon of 10 years

Market-based Investment in Electricity Transmission Networks: Controllable Flow

This paper discusses unregulated market-based electricity transmissio

Optimal configuration of hybrid AC/DC urban distribution networks for high penetration renewable energy

Existing AC medium-voltage distribution networks are facing challenges on handling increasing loads and renewable energy integrations. However, it is very difficult to build new distribution lines in urban areas. This study proposes a configuration method of hybrid AC/DC medium-voltage distribution networks, in which some existing AC lines are converted to DC operation. Existing topologies and dispatching scenarios are considered during configuration because the overall power flow can be rescheduled in the hybrid AC/DC distribution network. Therefore, transfer capacities of the lines are fully utilised, and more renewable energies are accommodated. A bi-level programming model is established embedding chance constraint programming to consider the intermittent output of renewable energy. In the upper level, a multiple objective optimal model is proposed in order to balance investments, power losses, and the maximum load level and renewable energy capacity. In the lower level, daily operations of the newly installed VSCs are optimised by a chance constraint programming. The influences of energy storage systems on the configuration are also analysed. Simulation studies are performed to verify the proposed method

Market-based Investment in Electricity Transmission Networks: Controllable Flow

This paper discusses unregulated market-based electricity transmission investment by third parties as opposed to regulated investment by designated transmission system operators. The analysis is set against a European and Australian institutional background and focuses on interconnection of different systems. The paper explores four areas: economies of scale, market power, detrimental investment and risks. The analysis argues for restricting market-based investment to controllable flow (DC or FACTS) only. This is in line with what seems to take place in practice in Europe and Australia, it strikes a balance between pros and cons of market-based investment and draws a sharp line between regulated and unregulated investments.electricity, transmission, merchant, investment

Development of Cal Poly’s Hybrid AC/DC House

The Hybrid House provides an example for what sustainable housing solutions could look like. It also functions as a potential solution to the current rural electrification issues many developing countries face. The use of a DC-DC MISO converter allows for combining multiple power sources into a single DC bus. The Hybrid House integrates the DC bus by employing the use of DC-DC converters for home use. This system may potentially improve the overall system efficiency by avoiding the losses associated with AC-DC converters. The use of the DC bus further leverages the Solar Panel renewable energy solution to become a more formidable power solution. This increased efficiency aligns with the overall goal of the Hybrid House which is to utilize mostly renewable energy in a home while still having the capability of integrating the grid power. Consequently, the Hybrid AC-DC House also offers an alternative solution for future sustainable house with improved reliabilit

EcoBlock: Grid Impacts, Scaling, and Resilience

Widespread deployment of EcoBlocks has the potential to transform today's electricity system into one that is more resilient, flexible, efficient and sustainable. In this vision, the system will consist of self- su cient, renewable-powered, block-scale entities that can deliberately adjust their net power exchange and can optimize performance, maintain stability, support each other, or disconnect entirely from the grid as needed. This report is intended as an independent analysis of the potential relationships, both constructive and adverse, between EcoBlocks and the grid

HVDC transmission : technology review, market trends and future outlook

HVDC systems are playing an increasingly significant role in energy transmission due to their technical and economic superiority over HVAC systems for long distance transmission. HVDC is preferable beyond 300–800 km for overhead point-to-point transmission projects and for the cable based interconnection or the grid integration of remote offshore wind farms beyond 50–100 km. Several HVDC review papers exist in literature but often focus on specific geographic locations or system components. In contrast, this paper presents a detailed, up-to-date, analysis and assessment of HVDC transmission systems on a global scale, targeting expert and general audience alike. The paper covers the following aspects: technical and economic comparison of HVAC and HVDC systems; investigation of international HVDC market size, conditions, geographic sparsity of the technology adoption, as well as the main suppliers landscape; and high-level comparisons and analysis of HVDC system components such as Voltage Source Converters (VSCs) and Line Commutated Converters (LCCs), etc. The presented analysis are supported by practical case studies from existing projects in an effort to reveal the complex technical and economic considerations, factors and rationale involved in the evaluation and selection of transmission system technology for a given project. The contemporary operational challenges such as the ownership of Multi-Terminal DC (MTDC) networks are also discussed. Subsequently, the required development factors, both technically and regulatory, for proper MTDC networks operation are highlighted, including a future outlook of different HVDC system components. Collectively, the role of HVDC transmission in achieving national renewable energy targets in light of the Paris agreement commitments is highlighted with relevant examples of potential HVDC corridors

Study of power management technology for orbital multi-100KWe applications. Volume 2: Study results

The preliminary requirements and technology advances required for cost effective space power management systems for multi-100 kilowatt requirements were identified. System requirements were defined by establishing a baseline space platform in the 250 KE KWe range and examining typical user loads and interfaces. The most critical design parameters identified for detailed analysis include: increased distribution voltages and space plasma losses, the choice between ac and dc distribution systems, shuttle servicing effects on reliability, life cycle costs, and frequency impacts to power management system and payload systems for AC transmission. The first choice for a power management system for this kind of application and size range is a hybrid ac/dc combination with the following major features: modular design and construction-sized minimum weight/life cycle cost; high voltage transmission (100 Vac RMS); medium voltage array or = 440 Vdc); resonant inversion; transformer rotary joint; high frequency power transmission line or = 20 KHz); energy storage on array side or rotary joint; fully redundant; and 10 year life with minimal replacement and repair

Network reinforcement requirements for Scotland and the rest of the UK (RUK) - and possible solutions for this

A novel multi-objective transmission expansion planning (MOTEP) tool has been developed to analyse, on a comprehensive geographical scale, the reinforcements required to a base case electrical transmission network following application of a chosen future energy scenario, and to generate optimal network expansion plans, designed to alleviate these areas of strain, for a range of crucial network planning objectives. Here, we report the application of the MOTEP tool to a base case predicted 2014 GB transmission network (thereby including already planned reinforcements such as the Beauly to Denny line) under heavy strain from three 2020 energy scenarios developed by the two-region UK MARKAL energy system model. Reinforcement requirements for Scotland and the RUK beyond 2014, along with optimal network expansion plan options, are examined