[6] Lin Boqiang, Wu Wei. Cost of long distance electricity transmission in China[D]. Energy Policy, 109, 132-140(2017).

[8] Coelli T J, Gautier A, Perelman S et al. Estimating the cost of improving quality in electricity distribution: A parametric distance function approach[D]. Energy Policy, 53, 287-297(2013).

[9] Jamasb T, Orea L, Pollitt M. Estimating the marginal cost of quality improvements: The case of the UK electricity distribution companies[D]. Energy Economics, 34, 1498-1506(2012).

[10] Corton M L, Zimmermann A, Phillips M A. The low cost of quality improvements in the electricity distribution sector of Brazil[D]. Energy Policy, 97, 485-493(2016).

[11] Cambini C, Croce A, Fumagalli E. Output-based incentive regulation in electricity distribution: Evidence from Italy[D]. Energy Economics, 45, 205-216(2014).

[12] Arcos-Vargas A, Núez-Hernández F, Villa-Caro G. A DEA analysis of electricity distribution in Spain: An industrial policy recommendation[D]. Energy Policy, 102, 583-592(2017).

[13] Agrell P J, Tind P B. DEA and dynamic yardstick competition in scandinavian electricity distribution[D]. Journal of Productivity Analysis, 23, 173-201(2005).

[14] Gouveia M C, Dias L C, Antunes C H et al. Benchmarking of maintenance and outage repair in an electricity distribution company using the value: Based DEA method[D]. Omega, 53, 104-114(2014).

[15] Llorca M, Orea L, Pollitt M G. Efficiency and environmental factors in the US electricity transmission industry[D]. Energy Economics, 55, 234-246(2016).

[16] Pereira De Souza et al. An application of data envelopment analysis to evaluate the efficiency level of the operational cost of Brazilian electricity distribution utilities.[D]. Socio-Economic Planning Sciences, 48, 169-174(2014).

[17] Fares R L, King C W. Trends in transmission, distribution, and administration costs for U.S. investor-owned electric utilities[D]. Energy Policy, 105, 354-362(2017).

[18] Kopsakangas-savolainen M, Svento R. Estimation of cost-effectiveness of the finnish electricity distribution utilities[D]. Energy Economics, 30, 212-229(2008).

[19] Bjorndal E, Bjorndal M H, Cullmann A et al. Finding the right yardstick: Regulation under heterogeneous environments[D]. European Journal of Operational Research, 265, 710-722(2016).

[20] Yatchew A. Incentive regulation of distributing utilities using yardstick competition[D]. Electricity Journal, 14, 56-60(2001).

[34] Scheel H. Undesirable outputs in efficiency valuations[D]. European Journal of Operational Research, 132, 400-410(2001).

[35] Liu Wenbin, Wei Meng, Li Xiangtang et al. DEA models with undesirable inputs and outputs[D]. Annals of Operations Research, 173, 177-194(2010).