A method to estimate the costs and benefits of undergrounding electricity transmission and distribution lines

Abstract

There has been a general shortfall of peer-reviewed literature identifying methods to estimate the costs and benefits of strategies employed by electric utilities to improve grid resilience. This paper introduces-for the first time-a comprehensive analysis framework to estimate the societal costs and benefits of implementing one strategy to improve power system reliability: undergrounding power transmission and distribution lines. It is shown that undergrounding transmission and distribution lines can be a cost-effective strategy to improve reliability, but only if certain criteria are met before the decision to underground is made.

Exploratory analysis of high-resolution power interruption data reveals spatial and temporal heterogeneity in electric grid reliability

“…Our results show that this approximation overestimates damages for the 70% of power interruptions that are shorter than the mean, while underestimating damages (potentially by orders of magnitude) for the 30% of power interruptions that are longer than the mean. It is unclear whether more granular information would increase or decrease overall damage estimates such as those reported in [10] and [23]. Implication 2 underscores the need for further research characterizing damages due to long-duration power interruptions, as damage functions reported in Sullivan et al [15] (and applied in [10,23]) are only valid for power interruptions shorter than 8 hours.…”

“…It is unclear whether more granular information would increase or decrease overall damage estimates such as those reported in [10] and [23]. Implication 2 underscores the need for further research characterizing damages due to long-duration power interruptions, as damage functions reported in Sullivan et al [15] (and applied in [10,23]) are only valid for power interruptions shorter than 8 hours. Based on our records, nearly 8% of power interruptions include some customers who remain without service for more than 8 hours.…”

“…In light of the barriers to securing proprietary data from multiple utilities, publicly reported information are better suited to support these efforts. Several studies in the literature aim to capitalize on these datasets, for example to report on trends in grid performance [6,7,8], to quantify the implications of power interruptions [9] and to explore the reliability benefits of different undergrounding policies [10].Further efforts have also been made to develop explanatory models for correlating reliability metrics with local weather patterns [7,11].Several of these studies leave questions unanswered, citing low-resolution in the data they use as both a limitation of the analysis they performed and a barrier to future work [6,7,12]. This raises questions about whether there are policy implications associated with leaving these research questions unanswered, whether more granular reliability data could advance policy research, and if so whether collection of more granular data is warranted.Multiple studies examining national grid performance report that the frequency of power interruptions is increasing [6,7,8].…”

The Frequency Characteristics of Mixed Power Networks with Partial Undergrounding

“…a) The reduced exposure to the adverse environmental and weather conditions b) The narrower required corridors and right-of-ways c) The weaker surrounding magnetic field d) The reduced nontechnical losses, [1][2][3][4][5] On the other hand, the following disadvantages should be taken into consideration: a) The resulting increase in the line cost b) The higher cable charging capacitive reactive power, [1] c) The cost of eventually required shunt reactors d) The increased secondary arc currents associated with the single-pole auto-reclosure and singlephase-to-ground faults, [6] e) The impact of the eventually needed shunt reactive power compensation on the power system's transient stability, [7].…”

“…There is a growing interest in the new concept of the partial undergrounding of high voltage networks comprising overhead transmission lines [1][2][3][4][5][6][7][8][9][10][11][12][13]. It is defined as the replacement of parts of these lines by adequate underground cable sections.…”