A New Approach for Benefit Evaluation of Multiterminal VSC–HVDC Using A Proposed Mixed AC/DC Optimal Power Flow

Abstract

In this paper, an extended optimal power-flow (OPF) model incorporating a detailed model of a voltage-source converter-based-multiterminal high-voltage direct current system (VSC-MTDC) is proposed, hereafter referred to as the mixed ac/dc OPF (M-OPF) model. A cost-benefit analysis approach using the M-OPF model as the calculation engine is proposed to determine the preferred VSC-MTDC alternative to be installed in an existing ac transmission system. In this approach, the operational benefits of VSC-MTDC systems are evaluated against their investment costs to derive the benefit-to-cost ratios (BCR) which reflect the cost-effectiveness of the alternatives. A case study has been carried out using a modified Nordic 32-bus system. The results of the study show that VSC-MTDC systems might lead to a reduction in total operation cost, and the reduction of the total system transmission loss depends to a large extent on the VSC-MTDC configuration. The results from sensitivity analyses show that if the VSC loss could be reduced to a third of the original level, the total benefit from the system would be increased by about 70%. A suggestion for the placement and configuration of a VSC-MTDC system is made based on calculated BCRs.

Loss minimization in wind farm integrated AC/DC system by optimal injections and droop settings of VSC-MTDC systems

“…Optimization parameters: Operating constraints, AC and DC bus voltage limits, AC and DC line transmission capacity limits, active and reactive power limits of the converter transformer, and operating constraints of converters are considered conventionally, as given in [14,15]. Figure 3 illustrates the proposed OPF algorithm.…”

“…The impacts of different DC grid topologies, such as serial, radial, and mesh topologies for various congestion pockets, are investigated for high wind power penetrations. This is done as a preoptimization problem, as given in [14]. A serial topology of the meshed DC system is taken as the test system, as shown in Figure 7.…”

“…As a preoptimization problem, the topology of the DC subsystem is chosen based on rigorous cost/benefit analysis [14]. The VSC-MTDC system considered is meant for network reinforcement of an AC transmission system, evacuating wind power.…”

Information gap decision theory based OPF with HVDC connected wind farms

“…• Cost benefit analysis for the operational benefits against the investment costs of HVDC systems [26] • Opportunity cost of wind power shortage & surplus [27] • Cost of environmental benefit loss [27] • Minimizing losses within the wind farm and the HVDC transmission system and maximizing production [28] • Expected penalty cost for wind power curtailment [29] • Expected cost of calling up power reserves because of wind power shortage [29] • Risk due to expected energy not supplied (EENS) and total operating costs [30] • Location marginal prices, and reserve costs [30] • Voltage regulation of the electrical grid [31] C. Contributions…”

Adaptive Firefly Algorithm based OPF for AC/DC Systems

“…Flexible and fast DC controls provide efficient and desirable performance for a wide range of AC systems. The existing OPF problem can be modified to handle AC/DC systems [2][3]. The resulting optimization problem, designated as OPF with DC links (OPFDC), is a large scale, non-linear non-convex and multimodal optimization problem with continuous and discrete control variables.…”