This paper posits on a reasonable quantification of the intrinsic reliability offered by an existing transmission network structure for a given set of power transactions. We rely on the concept of transmission reliability margins in the lines, which act as safety nets to protect system security in the face of aleatory uncertainties in the availability of transmission lines and epistemic uncertainty in accounting for the load demand patterns. This is proposed to be used as an equitable basis to charge the users of transmission network, generation and load consumption entities alike, over and above the usage charges levied according to the 'extent-of-use' normative. Using the tandem combination of deterministic and probabilistic load flow studies in conjunction with power flow tracing procedures, we propose a step-by-step procedure to arrive at a novel transmission pricing methodology. A six-bus Roy Billinton Test System (RBTS) is employed to illustrate the conceptual feasibility and the computational procedure.

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Economic trading brought on by the introduction of markets in the realm of power systems has witnessed a drastic shift in the way customer-say is incorporated into reliability apportioning. As customers are the sole determinants of profit making ventures in the liberalized regime, it is imperative that they be provided with ample decision support through reliability management options for the selective implementation of nonuniform reliability. The emergent equivalence techniques take into account the structural changes that necessitate the transitional operational framework in the restructured scenario. They provide clientele with the customary adequacy indices such as Loss of Load Probability (LOLP) and Expected Energy Not Served (EENS), enabling them to choose their generation providers according to pre-defined desirable thresholds. In a move towards facilitating them with additional means to base their decisions on, this paper puts forward a philosophical modeling paradigm that investigates the feasibility of extending the hybrid approach of well-being analysis, which encompasses part deterministic and part probabilistic features, to a composite bilateral contracts market structure. In this work, reliability network equivalent techniques are deemed fit to be used in conjunction with power flow tracing methodology to pave the way for a realistic Failure Modes and Effects Analysis (FMEA) phase, potentially culminating in the evaluation of well-being indices. This information can be used by Gencos as a standard to evolve the reserve management criteria as per the customer expectations.

The onset of deregulation in the electric power sector in the recent years has brought to the fore several pronounced issues related to reliability management, necessitating a revamping of the metrics. The element of markets and economic trading introduced in the operations of power systems has seen a paradigm shift even in the way customer-say is incorporated into the reliability apportioning. In order to better appreciate the sea-changes brought forward by deregulation, identification of areas of evolving reliability research in the regulated regime goes a long way in dealing with their deregulated counterparts. This paper caters to the view to provide a pointer to the significant issues that can profoundly impact the reliability studies in the liberalized environment. Emphasis in this paper is placed on a bilateral market structure, where all participants of competitive trading have mutually agreed upon pre-defined contracts to trade energy. With a view to improvise upon the existing nascent reliability network equivalent techniques, a realistic state space selection methodology, crucial to the contingency effects' evaluation is proposed, which makes a novel use of power flow tracing procedures. This research work is intended to pave the way for robust reliability models that take into account all the structural and consequent operational transmutations in power systems, yielding a concrete possibility of implementing non-uniform reliability as per the user requirements — a situation that was not feasible in the earlier regime.

Abstract--Electric power industry deregulation has brought about the unbundling of generation, transmission and distribution services and as such, new techniques for reliability assessment are being developed to account for the consequent structural changes in the restructured environment through direct analytical techniques or stochastic simulation. To this end, reliability equivalent techniques have been proposed in recent literature and are continuously being improvised upon, especially for the multi-bilateral contracts market structure. Power flow tracing, a potential tool that has so far only been effectively employed in transmission pricing in the open access environment, is deemed to be equally effective in capturing the effect of structural and economic alterations for the purpose of reliability evaluation in the liberalized regime. This paper elaborates on the idea that when used in tandem with reliability equivalent methods, tracing is bound to improve the accuracy of the indices in vogue. The contribution of individual generators and loads to line flows is obtained using a graph theoretic approach, relying on the proportional sharing principle. This information is then proposed to be used in the transmission line Failure Modes and Effects Analysis (FMEA) phase of the established procedure of reliability network equivalents. Comparisons are drawn to highlight the computational as well as accuracy benefits accrued in doing so.