Peak Operation of Cascaded Hydropower Plants Serving Multiple Provinces

Shen, Jianjian; Cheng, Chuntian; Zhang, Jun; Lu, Jian‐yu

doi:10.3390/en81011295

Cited by 19 publications

(8 citation statements)

References 28 publications

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“…• The maximum ramping capacity for power generation Ph i h ,t − Ph i h ,t−1 ≤ Ph i h (13) where Ph i h denotes maximum ramping capacity of hydro plant i h in period t. The above constraint is considered to limit the extent of changes in generation between two adjacent periods.…”

Section: ) Hydropower Plant Constraintsmentioning

confidence: 99%

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Generation Scheduling of a Hydrothermal System Considering Multiple Provincial Peak-Shaving Demands

Shen

Wang

et al. 2019

IEEE Access

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There is a common lack of flexible power to quickly follow peak loads of many coal-dominated provincial power grids (PPGs) in China. A regional power grid (RPG) that covers several provinces is responsible for scheduling the power plants it manages and allocating their power to subordinate PPGs in response to different peak loads. This process is more difficult than conventional peak operations for a single PPG. A methodology for hydrothermal system generation scheduling considering multiple provincial peak-shaving demands is developed. This methodology utilizes a novel load subsection optimization model to smooth local frequent load fluctuations. The model divides the provincial load curve into several subsections to construct an expected residual load profile with the average load of each subsection in advance. Minimizing deviation between the expected and calculated load profiles is then formulated as the optimization objective. Three practical algorithms, named the multistep progressive optimality algorithm, the heuristic algorithm, and an improved load shedding method, are integrated to determine the power generation for hydropower plants, pumped-storage plants, and thermal plants, respectively. Moreover, a variable neighborhood search algorithm is proposed to coordinate the allocation of the power generation among PPGs. This methodology has been implemented for the operations of the East China Grid, which is the largest RPG in China. Comparisons with an existing optimization model and a conventional method are, respectively, given in two cases. The first case shows that the peak-shaving demands in subordinate PPGs are effectively met. The load fluctuations in local hours are smoothed, with an average reduction of 6.3% in allan variance of residual loads. The second case implies that the proposed method deals better with the load differences in multiple power grids. It should also be noted that the operating flexibility of different power plants has a significant effect on smoothing fluctuations in residual loads.INDEX TERMS Peak-shaving, generation scheduling, load subsection optimization model, multiple provincial power grids, neighborhood search algorithm.

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Section: ) Hydropower Plant Constraintsmentioning

confidence: 99%

“…Their models relate only to the maximum and minimum of residual load series during optimization. Shen et al [13] and Feng et al [14] formulated the peak-shaving model by minimizing the mean square deviation of the residual load series. The model requires the daily energy target of each power plant.…”

Section: Introductionmentioning

confidence: 99%

Generation Scheduling of a Hydrothermal System Considering Multiple Provincial Peak-Shaving Demands

Shen

Wang

et al. 2019

IEEE Access

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“…Because of a locally underdeveloped economy, the major part of electricity from these plants is transmitted to load centers in eastern and coastal China via ultrahigh voltage direct current (UHVDC) lines. In particular, some large hydropower projects need to simultaneously undertake the electric supply for multiple regions or provinces [5,6]. For example, the famous Three Gorges Project is connected to three big regional power grids to serve their subordinate provinces.…”

Section: Introductionmentioning

confidence: 99%

Optimal Operation of Interprovincial Hydropower System Including Xiluodu and Local Plants in Multiple Recipient Regions

et al. 2019

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This paper focuses on the monthly operations of an interprovincial hydropower system (IHS) connected by ultrahigh voltage direct current lines. The IHS consists of the Xiluodu Hydropower Project, which ranks second in China, and local plants in multiple recipient regions. It simultaneously provides electricity for Zhejiang and Guangdong provinces and thus meets their complex operation requirements. This paper develops a multi-objective optimization model of maximizing the minimum of total hydropower generation for each provincial power grid while considering network security constraints, electricity contracts, and plant constraints. The purpose is to enhance the minimum power in dry season by using the differences in hydrology and regulating storage of multiple rivers. The TOPSIS method is utilized to handle this multi-objective optimization, where the complex minimax objective function is transformed into a group of easily solved linear formulations. Nonlinearities of the hydropower system are approximatively described as polynomial formulations. The model was used to solve the problem using mixed integer nonlinear programming that is based on the branch-and-bound technique. The proposed method was applied to the monthly generation scheduling of the IHS. Compared to the conventional method, both the total electricity for Guangdong Power Grid and Zhejiang Power Grid during dry season increased by 6% and 4%, respectively. The minimum monthly power also showed a significant increase of 40% and 31%. It was demonstrated that the hydrological differences between Xiluodu Plant and local hydropower plants in receiving power grids can be fully used to improve monthly hydropower generation.

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“…References [22] and [23] formulated a linear programming (LP) and a nonlinear programming (NLP) optimization model, respectively, for the power allocation among multiple power grids. Reference [24] proposed a two-stage search method to determine the shortterm generation scheduling of the cascaded hydropower plants transmitting electric power to multiple power grids through trans-provincial HVAC tie-lines. Reference [25] focused on determining the generation scheduling of a hydrothermal system which are required to satisfy the peakshaving demands of multiple provincial power grids.…”

Section: Introductionmentioning

confidence: 99%

Optimization Model for the Short-Term Operation of Hydropower Plants Transmitting Power to Multiple Power Grids via HVDC Transmission Lines

Wang

Shen

2019

IEEE Access

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Long-distance and large-capacity hydropower transmission from large hydropower plants in southwestern China to load centers is an important and effective measure for the accommodation of largescale hydropower in China. However, the load demands of the receiving-end power grids are not fully considered in the conventional power transmission mode, which has greatly affected their enthusiasm for the absorption of trans-regional hydro energy. In order to make full use of the peak shaving capability of the hydropower plants, this paper develops an optimization model for determining the hourly generation scheduling of the hydropower plants transmitting electric power to several power grids via high voltage direct current (HVDC) transmission lines. A large-capacity and highly complex multi-unit hydropower system, the Xiluodu plant in China, is taken as the case study. In the proposed model, minimizing the peak-valley differences of multiple receiving-end power grids is adopted as the objective to alleviate the peak shaving pressure of the receiving-end power grids. In addition to the traditional hydraulic constraints, the operation constraints of individual units and HVDC power transmission limits are well considered. The study focuses mainly on modeling the stair-like power transmission curve constraint which is discrete and nonlinear and has been rarely considered in previous studies. This constraint is then linearized through limiting the logical relations between multiple binary integer variables. Case studies demonstrate that the proposed model has high computational efficiency, and the peak-valley differences of the two receiving-end power grids, i.e., Zhejiang Power Grid and Guangdong Power Grid, are decreased by 15.2% and 7.33%, respectively. Moreover, frequent conversion of HVDC converter equipment can also be avoided, which makes the obtained generation schedule more executable.INDEX TERMS Hydropower plants, high voltage direct current, power transmission limits, peak shaving, Xiluodu plant. NOMENCLATURE A. SETS AND INDICES China, in 1965. He received the Ph.D. degree in hydraulic engineering from the

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Peak Operation of Cascaded Hydropower Plants Serving Multiple Provinces

Cited by 19 publications

References 28 publications

Generation Scheduling of a Hydrothermal System Considering Multiple Provincial Peak-Shaving Demands

Generation Scheduling of a Hydrothermal System Considering Multiple Provincial Peak-Shaving Demands

Optimal Operation of Interprovincial Hydropower System Including Xiluodu and Local Plants in Multiple Recipient Regions

Optimization Model for the Short-Term Operation of Hydropower Plants Transmitting Power to Multiple Power Grids via HVDC Transmission Lines

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