Mechanism and Characteristics analysis of Ultra-low Frequency Oscillation phenomenon in a Power Grid with a High Proportion of Hydropower

Teng, Yufei; Zhang, Peng; Han, Run; Fan, Chunju; Wang, Xiaoru; Jiang, Zhe; Zhang, Chun; Sun, Yongchao; Gong, Yanzhang; Yi, Jianbo

doi:10.1109/powercon.2018.8602179

Cited by 9 publications

(5 citation statements)

References 9 publications

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“…Based on the above two equations, the participating factors can be obtained from (14), where Φ ki and ψ ik are the kth term of Φ i and ψ i , respectively. The element p ki reflects the participation of the kth state variable in the ith mode…”

Section: The Participating Factor Analysismentioning

confidence: 99%

“…As for the eigenvalue method, it was concluded that the ULFO phenomenon was closely related to the hydraulic governor according to the hydraulic units' state variables analysis obtained by the small-signal model [13][14][15][16]. Considering nonlinear or coupled characteristics of the system, the conclusion that the primary frequency regulation of the hydraulic units was the source of ULFO was obtained.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

The occurrence mechanism and damping method of ultra‐low‐frequency oscillations

Wang

Liu

Jiang

et al. 2021

IET Renewable Power Gen

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The ultra‐low‐frequency oscillation (ULFO) problem has reappeared in China recently. Although the hydraulic generator is supposed to have a strong connection to this problem, the conditions for ULFO appearance and detailed reasons are not clear yet. In order to clarify the occurrence mechanism of ULFO, this paper studies each important part of hydraulic generator system, including the governor, exciter and power system stabiliser (PSS). The weak connection is confirmed to have an important impact on the occurrence of the ULFO. Nevertheless, by studying each device's contribution to ULFO through the complex torque coefficient method, it is shown that the negative damping effect of the hydraulic governor will cause the instability in the ultra‐low‐frequency band, while the exciter and the PSS have little influence on ULFO. Additionally, the proportional–integral parameters of the hydraulic governor system are also studied to clarify their influence on ULFO based on the complex torque coefficient method. Based on the above analysis, two damping methods for ULFO suppression are finally proposed. To verify theory and damping methods, the simulations are implemented in PSCAD and PSASP software.

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Section: The Participating Factor Analysismentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

The occurrence mechanism and damping method of ultra‐low‐frequency oscillations

Wang

Liu

Jiang

et al. 2021

IET Renewable Power Gen

View full text Add to dashboard Cite

show abstract

“…Reference [6] calculated the participation factor of the individual state variable in the ULFO mode, unveiling the contribution of the individual variable to the ULFO. Reference [7] investigated the main factors affecting the damping level of the system, including the water hammer effect and the unit operation level.…”

Section: Introductionmentioning

confidence: 99%

Research on Ultra-Low-Frequency Oscillation Suppression Method of High-Head, Large-Capacity Hydropower Units

Zhang,

Li,

Liu

et al. 2024

Energies

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Aiming at the problem of ultra-low-frequency oscillation (ULFO) caused by an irrational setting of governor parameters of high-head hydraulic turbine units, this paper proposes a method to optimize the additional damping control parameters of the governor to suppress ULFO. Firstly, the mechanism of ULFO is elaborated and the effect of system damping torque on ULFO is analyzed. Secondly, Hamilton’s theory is used to rank the magnitude of each unit’s contribution to the ULFO. Then, the parameters of the damping controller are optimized using the variational modal decomposition–Hilbert transform method and the Grey Wolf Optimization algorithm. It realizes the phase compensation of the hydroelectric unit governor and suppresses the ultra-low-frequency oscillation. Finally, the proposed method is validated using the simulation conducted in CloudPSS. The test results indicate that the proposed method can effectively suppress the ULFO caused by the high-head hydroelectric unit.

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“…Thus, the possibility of ULFO was reduced. Yufei Teng et al [10] found that when ULFO occurred, all synchronous generators oscillated synchronously, and the water hammer effect had the highest participation in the oscillation mode, while the participation of the excitation system was 0. Dong Liu et al [11][12] established a fine nonlinear model for the regulation system of three-engine turbine with common tail-tunnel arrangement, studied the variation rule of damping of hydropower unit with hydropower network structure and operating condition from two dimensions of hydraulic coupling and electrical coupling, and revealed the influence mechanism of hydraulicmechanical -electrical coupling on unit damping.…”

Section: Introductionmentioning

confidence: 99%

Analysis of ultra-low frequency oscillation mechanism of hydraulic turbine governor under different control modes

Li,

Feng,

Zheng

2024

J. Phys.: Conf. Ser.

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As the southwest power grid with a high proportion of hydropower was transformed into UHV AC-DC network structure, some ultra-low frequency oscillations have appeared in the power grid. In this paper, according to the characteristics of the hydropower unit governor, a small disturbance model was established, and the influence of various parameters of the hydropower unit governor on the system stability in primary frequency modulation was discussed by using the eigenvalue analysis method, and the power mode and the opening mode were compared. The results showed that the parameter adjustable range of the opening mode was larger than that of the power mode. This paper lays a foundation for further research on suppression methods of ultra-low frequency oscillations.

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Mechanism and Characteristics analysis of Ultra-low Frequency Oscillation phenomenon in a Power Grid with a High Proportion of Hydropower

Cited by 9 publications

References 9 publications

The occurrence mechanism and damping method of ultra‐low‐frequency oscillations

The occurrence mechanism and damping method of ultra‐low‐frequency oscillations

Research on Ultra-Low-Frequency Oscillation Suppression Method of High-Head, Large-Capacity Hydropower Units

Analysis of ultra-low frequency oscillation mechanism of hydraulic turbine governor under different control modes

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