Energy Conversion and Economics最新文献

Multi-energy microgrids could result in more flexibility and increase reliability by interconnecting networks. Electricity and gas networks exhibit very different dynamic behaviours in response to a fault or failure. Gas networks have built-in energy storages that can continue to provide a reliable supply if gas inputs to the system are compromised. This study presents a novel reliability assessment method applied to multi-energy microgrids; the method combines an incidence matrix analysis that identifies the connectivity between sources and load points with a sequential Monte Carlo simulation and generation adequacy evaluation. A case study is conducted by using an electricity-gas microgrid. The electricity network is a multi-sourced grid, whereas the gas network is supplied by a biogas plant. The linepack (gas stored along the pipelines) is modelled to account for the slower gas dynamics. The proposed method is evaluated on a real-world electricity distribution network in Austria. The results indicate the reliability benefits of forming a multi-energy microgrid.

A microgrid with a solar photovoltaic (SPV) array, wind generator, battery energy storage (BES), and a bidirectional DC–DC converter with seamless transition capability from on-grid mode (OGM) to off-grid mode (FGM) and grid reconnected mode is presented. This microgrid, based on renewable sources, increases the authenticity and sustainability of the supply and has the ability to feed the load in OGM and FGM as well as during mode shifting. The undetermined disturbances and unpredictability of the microgrid in OGM are managed by a sixth-order complex filter (6thOCF)-based control. With this control, the load current quadrature fundamental component (LCFC-Q) is obtained without a DC offset even during voltage imbalances. This control provides effective mitigation of harmonics and monitors the flow of active power, which improves the grid current quality. The control approach based on a resonant plus proportional resonant (R+PR) controller along with the harmonics compensation ability is used to control the microgrid in FGM. A dual 6thOCF (D6thOCF) is cascaded in series with the phase-locked loop for effortless synchronization of the grid. This enhances the system performance without affecting the stability. The microgrid performance is validated through simulated and experimental results under dynamic and steady-state conditions.

A strategic phasor measurement unit (PMU) placement scheme is proposed in this work to reduce the cyber vulnerability of the power system against cyber attacks. A multi-stage PMU placement strategy is developed to alleviate the power system vulnerability against the possible false data injection attacks using the forward dynamic programming to distribute the capital cost of PMUs over a time horizon. An index is also proposed to quantify the vulnerability of the nodes of a grid against false data injection attacks. This index is useful in selecting the optimal set of candidate buses for PMUs placement and prioritising the candidate buses for PMUs placement in a specific deployment stage. The proposed scheme will also ensure the critical observability of the grid in its first stage and increment in observability levels in subsequent stages. Simulation results are provided for IEEE 14-bus, IEEE 39-bus, and IEEE 118-bus test systems, considering the impact of zero injection buses (ZIBs) on optimisation process, to justify the effectiveness of the proposed index and PMUs placement approach.

Natural gas generators are promising devices for reducing greenhouse gas emissions. However, gas generators encounter difficulties in the bid-to-sell process based on a relatively high levelised cost of energy for power generation. Therefore, a novel risk hedging strategy is developed based on the mean-variance portfolio theory to reduce the operational risks of gas generators and enhance their profits. Three types of options are utilised and combined to form a portfolio of financial hedges: the short put option, long put option, and short call option. Two types of energy storage devices are used to facilitate the risk hedging process, namely power-to-gas and battery devices. Simulation results demonstrate that the proposed risk hedging model can ensure higher profits for gas generators with reduced risk compared to the traditional risk hedging model and a model using only one type of option. Additionally, the varied risk preferences of gas generators lead to varied portfolio combinations. The more risk averse a gas generator, the more likely the long-put option will be utilised. In contrast, the less risk averse a gas generator, the more likely that short calls will be utilised.

Auction mechanism analysis provides favourable economic outcomes for key stakeholders involved in the restructured power market. Real power pricing based on locational marginal pricing has been implemented in the electricity market worldwide. In this study, the optimal power flow is considered to minimise the operating cost of the active power generation in the ex-ante energy market and an augmented optimal power flow in the ex-ante reserve market. The double-sided auction mechanism has better control over the energy and reserve markets, enhancing social welfare in the restructured power markets. Single- and double-sided auction mechanisms are considered to analyse the allocation and pricing economics in the ex-ante day-ahead energy and ex-ante day-ahead reserve markets. Locational marginal pricing is calculated and analysed for both the on-and off-peak demand periods. The proposed auction model was validated using an IEEE 30-bus power system. The benefits of the double-sided auction are assessed from technical and economic perspectives.

This paper proposes the implementation of Affine Projection Sign Algorithm (APSA) based control for DSTATCOM to mitigate distribution side power quality issues like harmonic elimination, reactive power compensation, load balancing, power factor compensation, voltage regulation, etc. Affine projection algorithms have already finds application in power quality mitigation, but they suffer from high complexity and degraded performance due to impulsive interference. Whereas, sign algorithms are known to be robust against the impulsive noise and converges faster. Hence, sign algorithm with affine projection is proposed for mitigation of power quality problems in this work. APSA is used to estimate the reference active and reactive power component of polluted load current, which is further used to generate the reference signal for DSTATCOM. The performance of the algorithm is investigated for some real operating conditions of power system network in MATLAB/SIMULINK environment. The algorithm is tested in real-time simulator for validation. The result shows that the control algorithm is able to resolve distribution side power quality problems with fast convergence.

The large-scale application of electric vehicles can lead to new challenges in the operation of the two complex and coupled networks of electricity and transportation systems, thus creating a new concept—a power—traffic network. The purpose is to provide a comprehensive survey of this emerging field. First, both the transportation system and power grid models are briefly introduced in terms of time and space scales. Then, the power traffic network model and applications at long-term, mid-term, and short-term time scales are summarized, and provided a unified view of these achievements. Based on this analysis, recommendations for future research are presented.

This manuscript proposes a novel Solar-shunt active filter (solar-SHAF) controller for improving the power flow in a larger power-application. The proposed fault and non-linear detection unit (FANDU) avails faster disturbance detection. A novel FAND regulator (FANDR) is suggested to disconnect the solar power generation from the considered system within 10–12 s and the total inverter capacity is used for providing reactive power support to compensate the power fluctuation. A solar active power regulator (SAPR) is proposed to restore the active power output of the solar plant in a ramp-wise manner after the successful damping of the power fluctuations. The restoration of rated solar power results offers a faster settling time in comparison to the standard grid code limits. The proposed approach is applicable for light, dark, and partial shading conditions. During the dark period, the total inverter capacity is used to compensate the power fluctuations and in partial shading conditions, the inverter is used to balance the solar power at its rated limit. The overall system is designed and tested through MATLAB software by considering different test conditions. It is analyzed that the suggested approach facilitates a significant improvement in power exchange on a 24/7 basis during the local and inter-area fluctuating mode.

The continuous growth of renewable generation in power systems brings serious challenges to electricity markets due to their characteristics different from conventional generation technologies. These challenges come from two dimensions, including short-term (energy and ancillary service markets) and long-term (long-term bilateral and capacity markets) aspects. Under this background, the design of energy and ancillary service markets is studied for power systems with a high penetration level of variable renewable generation. In the proposed spot market mechanism, energy and frequency regulation service (FRS) bids are jointly cleared, where renewable generators are motivated to proactively manage the intermittency and uncertainty of their power outputs. The proposed market mechanism can also ensure the adequacy of FRS capacity for compensating variability of renewables. Besides, in order to ensure the execution of spot market clearing outcomes, this paper established a penalty scheme for mitigating the real-time fluctuations of renewable generation outputs in the spot market. Differences between real-time generation outputs and market clearing outcomes are managed within a certain limit by imposing the designed penalty prices on deviations. Finally, the feasibility and efficiency of the developed market mechanism and algorithms are manifested in the case studies.

Successful deployment of electric vehicles demands for establishment of simple reachable charging stations (CSs). Scheduling and action of CSs is a composite problem and that should not affect the smooth operation of the power grid. The present paper attempts to solve the planning and operation of CSs by a novel chicken swarm optimization-based heuristics. The placement of CS is modelled in a multi-objective framework as cost-effective parameters secures the operation of the power grid. Further, the operation of CSs is examined for three scenarios such as uncoordinated charging, coordinated charging, as well as bidirectional vehicle to grid. The proposed approach is tested on IEEE 33-bus, and on a distribution network of Guwahati, India.