Optimization Strategy of Hydrogovernors for Eliminating Ultralow-Frequency Oscillations in Hydrodominant Power Systems

Chen, Gang; Tang, Fan; Shi, Huabo; Yu, Rui; Wang, Guanhong; Ding, Lu; Liu, Baisi; Liu, Xiaonan

doi:10.1109/jestpe.2017.2788004

Cited by 48 publications

(35 citation statements)

References 9 publications

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“…First, by quitting the frequency regulation function of hydropwer generators with negative damping, the oscillation could be eliminated [25]. Second, some optimization methods for the PID parameters of hydropower governors were proposed, which take into account the tradeoff between the performance of primary frequency regulation and the suppression of ultralow-frequency oscillations [4]. In addition, some researchers have added a governor's power system stabilizer on the speed control side of a hydropower generator to increase its damping in the ultralow-frequency band, thereby suppressing ultralow-frequency oscillations [9].…”

Section: Actual System Of a County In Sichuan Province Chinamentioning

confidence: 99%

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Small-Signal Stability Analysis of Photovoltaic-Hydro Integrated Systems on Ultra-Low Frequency Oscillation

Wang¹,

Wu²,

Chen³

et al. 2020

Energies

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In recent years, ultralow-frequency oscillation has repeatedly occurred in asynchronously connected regional power systems and brought serious threats to the operation of power grids. This phenomenon is mainly caused by hydropower units because of the water hammer effect of turbines and the inappropriate Proportional-Integral-Derivative (PID) parameters of governors. In practice, hydropower and solar power are often combined to form an integrated photovoltaic (PV)-hydro system to realize complementary renewable power generation. This paper studies ultralow-frequency oscillations in integrated PV-hydro systems and analyzes the impacts of PV generation on ultralow-frequency oscillation modes. Firstly, the negative damping problem of hydro turbines and governors in the ultralow-frequency band was analyzed through the damping torque analysis. Subsequently, in order to analyze the impact of PV generation, a small-signal dynamic model of the integrated PV-hydro system was established, considering a detailed dynamic model of PV generation. Based on the small-signal dynamic model, a two-zone and four-machine system and an actual integrated PV-hydro system were selected to analyze the influence of PV generation on ultralow-frequency oscillation modes under different scenarios of PV output powers and locations. The analysis results showed that PV dynamics do not participate in ultralow-frequency oscillation modes and the changes of PV generation to power flows do not cause obvious changes in ultralow-frequency oscillation mode. Ultra-low frequency oscillations are mainly affected by sources participating in the frequency adjustment of systems.

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Section: Actual System Of a County In Sichuan Province Chinamentioning

confidence: 99%

“…According to researchers' studies, similar possible troubles of ultralow-frequency oscillations exist in Sichuan Power Grid in China, which also contains a large number of hydropower units. This problem can be triggered after asynchronous networking [4].…”

Section: Introductionmentioning

confidence: 99%

Small-Signal Stability Analysis of Photovoltaic-Hydro Integrated Systems on Ultra-Low Frequency Oscillation

Wang¹,

Wu²,

Chen³

et al. 2020

Energies

Self Cite

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“…The influence of key parameters such as time constant of water hammer effect and PID parameter of governor on ULFO has been analyzed in detail by root locus, parameter sensitivity and other methods [9][10][11][12][13]. The simulation text further shows that the damping and amplitude of the ULFO are closely related to the disturbance form, unit parameters and operation mode of the power The open-loop transfer function of the governor and turbine system in Figure 1 can be expressed as:…”

Section: Analysis Of Influencing Factorsmentioning

confidence: 99%

“…The asynchronous operation of the Southwest China Power Grid (SCPG) faced with an obvious risk of ULFO according to the simulation. The governor parameters optimization [10] and the DC frequency limit control (FLC) are adopted to suppress it. The asynchronous operation test of SCPG verifies the effectiveness of the strategy.…”

Section: Introductionmentioning

confidence: 99%

Research on Damping Control Index of Ultra-Low-Frequency Oscillation in Hydro-Dominant Power Systems

Chen¹,

Liu²,

Fan³

et al. 2020

Sustainability

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In recent years, ultra-low-frequency oscillation (ULFO) is a prominent problem in power systems of dominant hydropower. In order to suppress ULFO, the most effective strategy is the governor parameters optimization to improve the system damping within the ultra-low-frequency band. However, no explicit standard has been established to stipulate the level of system damping for ULFO suppression. In this paper, the key factors that affect the amplitude and damping of ULFO are firstly analyzed. Then, the design principle of the damping control index of ULFO is put forward. According to it, a damping control index is proposed. After that, a case of ULFO in an actual power system proves the rationality of the proposed index. Finally, the application of the index in the Southwest China Power Grid illustrates its effectiveness and feasibility.

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“…However, the mechanism of oscillation is not clear yet. In [14], a ultra-low frequency oscillation and suppression method in the Central Tibet and Sichuan power grids was introduced, but it did not involve electromagnetic oscillation. To suppress the oscillation, additional damping controllers are often used for low frequency oscillation, while less research has been carried out on the suppression of electromagnetic oscillation.…”

Section: Introductionmentioning

confidence: 99%

Optimization Strategy of SVC for Eliminating Electromagnetic Oscillation in Weak Networking Power Systems

Shi¹,

Sun²,

Chen³

et al. 2019

Energies

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The central Tibet AC interconnection project (CTAIP), which connects the Tibet power grid and the Sichuan power grid through a long distance transmission line of more than 1400 km, has a significant problem of voltage regulation. In order to improve the voltage regulation performance, six sets of ±60 Mvar static VAR compensators (SVC) were installed in the CTAIP. However, the SVCs may lead to electromagnetic oscillation below 50 Hz while improving voltage regulation capability. In this paper, the electromagnetic oscillation modes and the sensitivity of control parameters of SVC are analyzed. Then, the characteristics and influencing factors of the oscillation are discussed. It was found that there is an inherent electromagnetic oscillation mode below 50 Hz in the ultra-long distance transmission system. The employ of SVCs weaken the damping of this mode. Large proportional gain and integral gain (PI) parameters of SVCs can improve the voltage regulation performance, but weaken the electromagnetic oscillation mode damping. Therefore, a suppression method based on SVC PI parameters optimization is proposed to damp the oscillation. The essential of this method is to use the rising time of voltage response and setting time of SVCs as performance indicators of voltage regulation, and take the damping level of the electromagnetic oscillation mode as the performance index of SVC electromagnetic oscillation suppression ability. Combining the two indicators to form a comprehensive optimization index function, an intelligent optimization algorithm is applied. The process of SVC parameter optimization and the steps of multi-SVC parameter optimization in large power grids is proposed. Finally, PSCAD and real-time digital simulation (RTDS) simulation results verified the correctness of the proposed method. The optimization strategy was applied to CTAIP. The artificial grounding short circuit experimental results proved the effectiveness of the proposed strategy.

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Optimization Strategy of Hydrogovernors for Eliminating Ultralow-Frequency Oscillations in Hydrodominant Power Systems

Cited by 48 publications

References 9 publications

Small-Signal Stability Analysis of Photovoltaic-Hydro Integrated Systems on Ultra-Low Frequency Oscillation

Small-Signal Stability Analysis of Photovoltaic-Hydro Integrated Systems on Ultra-Low Frequency Oscillation

Research on Damping Control Index of Ultra-Low-Frequency Oscillation in Hydro-Dominant Power Systems

Optimization Strategy of SVC for Eliminating Electromagnetic Oscillation in Weak Networking Power Systems

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