Environmental Constrained Optimal Hybrid Energy Storage System Planning for an Indian Distribution Network

Abstract

In recent days, aiming for power generation with less carbon emission, led to the high penetration of renewable energy into the distribution grid. To improve the intermittency caused by renewables and to increase the grid flexibility, grid integrated Energy Storage Units (ESUs) are proposed as the promising solution in the literature. However, considering the investment cost, ESUs are optimally placed by satisfying the network electrical constraints. On the other hand, consideration of environmental impacts and other practical constraints are also equally important. Therefore, in this article, on top of grid performance parameters, realistic parameters that may affect the location and its size such as (1) environmental impact, (2) land requirement & its associated cost for ESU installation and (3) renewable purchase obligation are formulated in the objective function. Decision making on ESU installation is a planning activity, which follows uncertainty. Consequently, it is essential to model the uncertainty parameters into the objective function, for better planning. In this article, optimal planning of hybrid ESUs based on realistic parameters along with uncertainty is addressed. For this study, a practical 156-bus distribution system of Dehradun district, India is considered. From the results obtained, it is evident that, formulating hybrid ESU constrained with the environmental impact has significantly decreased the emission of CO2 with maximum grid stability. INDEX TERMS Batteries, distributed power generation, environmental economics, power system planning, sustainable development.

Effect of Unaccounted Parameters on Reactive Power Compensation in Indian Electric Traction Line

“…The figures on the cost effectiveness of Diesel Traction and Electrical Traction of Indian railways organization [3], which is indicated in Table 2 to substantiate it. Moreover, to achieve the UN SGDs goal [1], Indian Railways has implemented the world's first solar power plant to directly power overhead equipment.…”

“…The conventional method of power factor improvement is the 'injection of leading reactive power (kVAR lead) using static capacitors on a monthly average basis, connected in parallel to the load, at TSS as shown in figure 1 [26] [27]. The kVAR lead is determined by measuring one-month lagging reactive power caused by the railway traction load of any particular TSS [3], and railways prefer the power factor near to unity (Fig. 5).…”

“…The generalized model of high voltage electric traction line is shown in figure 3. Albeit, 25 kV electric traction line has no similarity with the power transmission line; its parameter modelling has been done with reference to a short transmission line model [22] [3]. EHV lines those have length 100 km or less, and a working voltage of 110 kV or below are classified as short transmission lines.…”

“…If the electric power supply company insist the consumers to maintain power factor close to unity at any load conditions will add fiscal burden to the consumers like; railway organizations, because the shifting of reactive power from lagging to leading and vice versa with the sudden variations in load in an unpredictable manner is very common in electric railway traction. It is learned [3][25] that the lagging reactive power in electric traction is seriously considered for design purpose. Generation of leading reactive power at OHE is found ruled out in the design stage itself.…”

“…To empower the whole railway network from solar PV power will face many challenges due to the intermittent nature of solar PV output. However, the proper combination of energy storage units and renewable energy sources (RES) can curb the uncertain nature of RES in railway electrification [3] [4] [5].…”