Coordinated operations of large-scale UHVDC hydropower and conventional hydro energies about regional power grid

Shen, Jianjian; Cheng, Chuntian; Xiong, Cheng; Lund, Jay R.

doi:10.1016/j.energy.2015.12.011

Cited by 51 publications

(17 citation statements)

References 26 publications

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“…Eq. (1) and (2) are defined based on the assumption of equal mutual fluxes along the axis. However, since the mutual leakage inductance is considered, it is no longer valid.…”

Section: B DC Step Voltage Testmentioning

confidence: 99%

“…For the d-axis test, the rotor position angle  is -30 o with that of the q-axis test is 60 o . The voltages and currents of both axes have the following relationship with that of the stator side, 3 2 3…”

Section: A Traditional DC Step Voltage Testmentioning

confidence: 99%

“…Ultra-high voltage direct current (UHVDC) transmission projects have seen a rapid uptake in some Asian countries in recent years [1,2]. To ensure the stable transmission of power, the converter stations of UHVDC systems need a large amount of reactive power, especially under conditions with more dynamic variation [3].…”

Section: Introductionmentioning

confidence: 99%

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Standstill Time-Domain Response Parameter Estimation of the Large Synchronous Condenser in Arbitrary Rotor Position

Zhou

Wang

2020

IEEE Access

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The necessity to align the rotor with the d-q magnetic axes is the main obstacle for the wide application of synchronous machine standstill parameter tests, especially for the high-power units. This paper presents an arbitrary rotor position parameter estimation method for standstill time-domain response (SSTRs) tests and applied on a 300 MVar, 20 kV large synchronous condenser, a DC step voltage signal is selected as the input signal. Firstly, a frequency-domain Dalton-Cameron transformation is demonstrated and used to simultaneously obtain both axes' operational inductances in an arbitrary rotor position, thus eliminating the need for the rotor prepositioning process. Then, a novel analytical parameter estimation method combined with an I/T transformation is proposed, all the parameters of both axes are determined without extra tests, the mutual leakage flux between the field winding and the d-axis damper winding is also taken in account. To validate the proposed method, this test is carried out and its parameter estimation results are compared against that of the three-phase sudden short-circuit test and the traditional SSTR test. Estimation results are given in the form of I-type and T-type circuits, the maximum relative error no more than 6% and 10%, respectively. INDEX TERMS Parameter estimation, large synchronous condenser, standstill time-domain response, arbitrary rotor position NOMENCLATURE uabc stator three-phase voltage us stator input voltage iabc stator three-phase current ud, uq d-and q-axis voltage, respectively id, iq d-and q-axis current, respectively uf field winding voltage if, iD field and damper winding current, respectively iQ1, iQ2 q-axis damper winding 1, 2 current, respectively Ld, Lq d-and q-axis synchronous inductance, respectively Lad, Laq d-and q-axis armature reaction inductance, respectively Lsl stator leakage inductance Lfl, Ldl field and damper winding leakage inductance, respectively LQl1, LQl2 q-axis damper winding 1, 2 leakage inductance, respectively L d ' , L d '' d-axis transient and sub-transient inductance, respectively L q '' , L q ''' q-axis sub-transient and sub-subtransient inductance, respectively T d ' , T d '' d-axis transient and sub-transient shortcircuit time constant, respectively T d0 ' , T d0 '' d-axis transient and sub-transient opencircuit time constant, respectively T q '' , T q ''' q-axis sub-transient and sub-subtransient short-circuit time constant, respectively T q0 '' , T q0 ''' q-axis sub-transient and sub-subtransient open-circuit time constant, respectively Tf, TD field and damper winding leakage time constant, respectively ra, rs stator and armature resistance, respectively rf, rD field and damper winding resistance, respectively rQ1, rQ2 q-axis damper winding 1, 2 resistance, respectively  rotor position angle

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“…Eq. (1) and (2) are defined based on the assumption of equal mutual fluxes along the axis. However, since the mutual leakage inductance is considered, it is no longer valid.…”

Section: B DC Step Voltage Testmentioning

confidence: 99%

Section: A Traditional DC Step Voltage Testmentioning

confidence: 99%

See 1 more Smart Citation

Standstill Time-Domain Response Parameter Estimation of the Large Synchronous Condenser in Arbitrary Rotor Position

Zhou

Wang

2020

IEEE Access

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“…According to the disturbance process of the power system, in the initial stage of the off-grid of the hydropower unit, all the units in the island system reach the same acceleration under the action of the synchronous torque before the governor operates. The rate of change of angular velocity and the frequency variation of the island system of all units in the island system can be calculated by the following formula [21,22]:…”

Section: Shp Isolated Network Operation Indicatorsmentioning

confidence: 99%

Study on Grid-Connected Strategy of Distribution Network with High Hydropower Penetration Rate in Isolated Operation

et al. 2019

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As the largest global renewable source, hydropower is a useful supplement to mountainous distribution networks with abundant water resources, and shoulders a large portion of the regulation duty in many power systems. In particular, in the form of decentralized energy sources located to their customers, small hydropower (SHP) improve grid stability by diversifying the electricity system and reducing power loss. The mountainous distribution networks supplied by small hydropower are closed-loop design but open-loop operation, which easily causes the tripping of tie line even further the off-grid operation of small hydropower system. Once the tie line trips, the current countermeasures—such as hydropower shutdown and load shedding—do not fully guarantee the reliability of power supply and the utilization efficiency of hydropower. This paper studies the amplitude-frequency characteristics of SHP off-grid, according to the typical integration of hydropower in South China, a SHP on-grid/off-grid model is established based on the Power Systems Computer Aided Design (PSCAD) platform. It is found that due to the inertia of SHP, the amplitude-frequency characteristics of SHP island system are relatively slow, and the process of non-synchronization with the main grid is gradually expanded. The characteristic of SHP has a certain degree of synchronization with the main grid in the initial island operates stage, which helps to find a novel grid connection method. This paper further proposes the strategy of using fast busbar automatic transfer switch (BATS), which quickly connect the trip-off SHP to the distribution network under the condition of permitting distributed energy grid-connected. The PSCAD simulation results show that proposed strategy has a limited impact on the power grid and prove the effectiveness of the method.

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“…Another example is the Xiluodu Hydropower Project (XHP), which provides electricity for Guangdong province in the southern region and Zhejiang province in the eastern region. Through the nationwide electricity transmission network, the large hydropower plants in southwest China have been widely connected with those in recipient regions and provinces, and thus interprovincial hydropower systems (IHSes) are formed [7].…”

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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Coordinated operations of large-scale UHVDC hydropower and conventional hydro energies about regional power grid

Cited by 51 publications

References 26 publications

Standstill Time-Domain Response Parameter Estimation of the Large Synchronous Condenser in Arbitrary Rotor Position

Standstill Time-Domain Response Parameter Estimation of the Large Synchronous Condenser in Arbitrary Rotor Position

Study on Grid-Connected Strategy of Distribution Network with High Hydropower Penetration Rate in Isolated Operation

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

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