Polymeric Tunable Optical Attenuator for Dynamic Channel Power Regulation in WDM Systems

1999 ◽  
Author(s):  
Sang-Shin Lee ◽  
Yong-Sung Jin ◽  
Yung-Sung Son ◽  
Jae-Hoon Jung ◽  
Ki-Woon Na
Keyword(s):  
Channel Power ◽  
Power Regulation ◽  
Dynamic Channel

Feedback controlled variable optical attenuator for channel power regulation in WDM systems

1999 ◽  
Vol 35 (11) ◽  
pp. 916 ◽  
Author(s):  
Yong-Sung Jin ◽  
Sang-Shin Lee ◽  
Yung-Sung Son
Keyword(s):  
Channel Power ◽  
Variable Optical Attenuator ◽  
Power Regulation

Dynamic-channel-equalizer using in-line channel power monitor and electronic variable optical attenuator

2007 ◽  
Vol 272 (1) ◽  
pp. 87-91 ◽  
Author(s):  
Y. Liu ◽  
C.W. Chow ◽  
C.H. Kwok ◽  
H.K. Tsang ◽  
Chinlon Lin
Keyword(s):  
Channel Power ◽  
Variable Optical Attenuator ◽  
Dynamic Channel

scholarly journals Power Hardware-in-the-Loop-Based Performance Analysis of Different Converter Controllers for Fast Active Power Regulation in Low-Inertia Power Systems

Energies ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3274
Author(s):  
Jose Rueda Torres ◽  
Zameer Ahmad ◽  
Nidarshan Veera Kumar ◽  
Elyas Rakhshani ◽  
Ebrahim Adabi ◽  
...  
Keyword(s):  
Performance Evaluation ◽  
Power Systems ◽  
Real Time ◽  
Control Strategies ◽  
Active Power ◽  
Power Electronic ◽  
Hardware In The Loop ◽  
Digital Controllers ◽  
Power Regulation ◽  
The Impact

Future electrical power systems will be dominated by power electronic converters, which are deployed for the integration of renewable power plants, responsive demand, and different types of storage systems. The stability of such systems will strongly depend on the control strategies attached to the converters. In this context, laboratory-scale setups are becoming the key tools for prototyping and evaluating the performance and robustness of different converter technologies and control strategies. The performance evaluation of control strategies for dynamic frequency support using fast active power regulation (FAPR) requires the urgent development of a suitable power hardware-in-the-loop (PHIL) setup. In this paper, the most prominent emerging types of FAPR are selected and studied: droop-based FAPR, droop derivative-based FAPR, and virtual synchronous power (VSP)-based FAPR. A novel setup for PHIL-based performance evaluation of these strategies is proposed. The setup combines the advanced modeling and simulation functions of a real-time digital simulation platform (RTDS), an external programmable unit to implement the studied FAPR control strategies as digital controllers, and actual hardware. The hardware setup consists of a grid emulator to recreate the dynamic response as seen from the interface bus of the grid side converter of a power electronic-interfaced device (e.g., type-IV wind turbines), and a mockup voltage source converter (VSC, i.e., a device under test (DUT)). The DUT is virtually interfaced to one high-voltage bus of the electromagnetic transient (EMT) representation of a variant of the IEEE 9 bus test system, which has been modified to consider an operating condition with 52% of the total supply provided by wind power generation. The selected and programmed FAPR strategies are applied to the DUT, with the ultimate goal of ascertaining its feasibility and effectiveness with respect to the pure software-based EMT representation performed in real time. Particularly, the time-varying response of the active power injection by each FAPR control strategy and the impact on the instantaneous frequency excursions occurring in the frequency containment periods are analyzed. The performed tests show the degree of improvements on both the rate-of-change-of-frequency (RoCoF) and the maximum frequency excursion (e.g., nadir).

scholarly journals Stability Analysis of Different Regulation Modes of Hydropower Units

Energies ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1933
Author(s):  
Xinran Guo ◽  
Yuanchu Cheng ◽  
Jiada Wei ◽  
Yitian Luo
Keyword(s):  
Stable Operation ◽  
Rotor Speed ◽  
Frequency Range ◽  
Power Regulation ◽  
Normal Frequency ◽  
Dynamic Performances ◽  
Negative Damping ◽  
The Stability ◽  
Regulation Mode ◽  
Water Inertia

The dynamic characteristics of hydropower unit governing systems considerably influence the stability of hydropower units and the connected power system. The dynamic performances of hydropower units with power regulation mode (PRM) and opening regulation mode (ORM) are different. This paper establishes a detailed linear model of a hydropower unit based on the Phillips–Heffron model. The damping characteristic and stability of two regulation modes with different water inertia time constants TW were analyzed. ORM tended to provide negative damping, while PRM often provided positive damping in the major parts of the frequency range within the normal frequency oscillations when TW was large. Eigenvalue analysis illustrated that PRM has better stability than ORM. To validate the analysis, a simulation under two typical faults WAS conducted based on a nonlinear model of a hydropower unit. The simulation results illustrated that the responses of units with PRM are more stable in terms of important operating parameters, such as output power, rotor speed, and power angles. For hydropower units facing challenges in stable operation, PRM is recommended to obtain good dynamic stability.

Optimal innovation investment: the role of subsidy schemes and supply chain channel power structure

2021 ◽  
Vol 157 ◽  
pp. 107291
Author(s):  
Chaofan Li ◽  
Qiliang Liu ◽  
Pin Zhou ◽  
Hongjun Huang
Keyword(s):  
Supply Chain ◽  
Power Structure ◽  
Channel Power
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