Modelling and control of slip power recovery schemes for small hydro power stations

2005 ◽  
Author(s):  
F.N. Okafor ◽  
W. Hofmann
Keyword(s):  
Hydro Power ◽  
Power Stations ◽  
Power Recovery ◽  
And Control ◽  
Recovery Schemes

scholarly journals Towards a balancing safety against performance approach in human–robot co-manipulation for door-closing emergencies

2021 ◽  
Author(s):  
Chuande Liu ◽  
Chuang Yu ◽  
Bingtuan Gao ◽  
Syed Awais Ali Shah ◽  
Adriana Tapus
Keyword(s):  
Loop Control ◽  
Risk Levels ◽  
Human In The Loop ◽  
Planning And Control ◽  
Power Stations ◽  
Markov Decision ◽  
Partially Observable ◽  
And Control ◽  
Self Protection ◽  
Balance Mechanism

AbstractTelemanipulation in power stations commonly require robots first to open doors and then gain access to a new workspace. However, the opened doors can easily close by disturbances, interrupt the operations, and potentially lead to collision damages. Although existing telemanipulation is a highly efficient master–slave work pattern due to human-in-the-loop control, it is not trivial for a user to specify the optimal measures to guarantee safety. This paper investigates the safety-critical motion planning and control problem to balance robotic safety against manipulation performance during work emergencies. Based on a dynamic workspace released by door-closing, the interactions between the workspace and robot are analyzed using a partially observable Markov decision process, thereby making the balance mechanism executed as belief tree planning. To act the planning, apart from telemanipulation actions, we clarify other three safety-guaranteed actions: on guard, defense and escape for self-protection by estimating collision risk levels to trigger them. Besides, our experiments show that the proposed method is capable of determining multiple solutions for balancing robotic safety and work efficiency during telemanipulation tasks.

scholarly journals Photogrammetric and Satellite Mapping of the Margin of the Inland Ice, West Greenland

1986 ◽  
Vol 8 ◽  
pp. 164-167 ◽  
Author(s):  
H.H. Thomsen
Keyword(s):  
Surface Feature ◽  
Aerial Photographs ◽  
Water Drainage ◽  
Feature Maps ◽  
Hydro Power ◽  
Surface Features ◽  
Power Stations ◽  
Run Off ◽  
Set Up ◽  
Inland Ice

Glaciological investigations have been carried out in areas proposed for local hydro-power stations in Greenland, A mapping programme was set up, to provide data for mass balance and simulation of run-off, as well as glacier dynamics.Two types of glacier map have been produced, covering the margin of the Inland Ice: detailed photogrammetric maps, based on plotting from vertical aerial photographs and a new type of surface feature map, based on digitally-processed Landsat data. The photogrammetric maps, plotted on a scale of 1:25 000, include surface topography and surface features, such as crevasses, lakes, moraines etc. The surface feature maps, plotted on a scale of 1:100 000, show surface features related to ice and melt-water drainage, as well as subtle, topographic features, related to the subglacial topography.The maps have so far been used for preliminary delineation of drainage areas on the Inland Ice and for planning tracks of radio echo-soundings.

Assessment of the Current and Expected by mid-XXI Century Climatic Changes at the Major Reservoirs Catchments of Russian Hydro Power Stations

2014 ◽  
pp. 60-71
Author(s):  
Keyword(s):  
Integrated Assessment ◽  
Climate Changes ◽  
Climatic Changes ◽  
Hydro Power ◽  
Hydrological Conditions ◽  
Power Stations ◽  
Hydropower Stations ◽  
Operational Modes

The paper presents an integrated assessment of trends in changing of climatic and hydrological conditions in contemporary period and for the 2041–2060 period within the zone of major national hydropower stations in order to specify operational modes and to prevent unfavorable consequences of climate changes for hydropower stations.

scholarly journals Insights into PCDD/Fs and PAHs in Biomass Boilers Envisaging Risks of Ash Use as Fertilizers

2020 ◽  
Vol 10 (14) ◽  
pp. 4951
Author(s):  
Helena Lopes ◽  
Susana Proença
Keyword(s):  
Unburned Carbon ◽  
Fly Ashes ◽  
Power Stations ◽  
Polycyclic Aromatic ◽  
Toxic Equivalents ◽  
One Year ◽  
Definition Of ◽  
And Control ◽  
The Impact ◽  
Biomass Ashes

Since ashes are a possible source of Persistent Organic Pollutants (POPs) contamination, their application in soils must be subject to more study and control. In this scope, feed residual forest biomasses and biomass ashes, collected along one year in four biomass power stations, were characterized mainly for their polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs) and Polycyclic Aromatic Hydrocarbons (PAHs) contents. The biomasses present concerning levels of Cl (0.04–0.28%) that may lead to PCDD/Fs formation. The biomasses also contain OCDD (29–260 ng/kg) and 1,2,3,4,6,7,8-HpCDD (35 ng/kg) that may contribute to increased Toxic Equivalents (TEQs) of ashes, possibly involving dechlorination and ash enrichment mechanisms. While the WHO2005-TEQs in bottom ashes (14–20 ng TEQ/kg) reaches the proposed limit (20 ng TEQ/kg) for ash use as fertilizers, in fly ashes (35–1139 ng TEQ/kg) the limit is exceeded. PAHs are below 0.02 mg/kg in bottom ashes and 1.5–2.5 mg/kg in fly ashes, complying with the proposed limit of 6 mg/kg. As bottom and fly ash streams may contain different ash flows, a clear definition of ash mixes is required. Correlations between unburned carbon (C), PAHs and PCDD/Fs were not found, which highlights the need for compulsory PCDD/Fs analysis in ashes, independently of their origin, burnout degree or levels of other contaminants. A sensitivity analysis was performed to evaluate the impact of handling non-detected values, which showed more impact for TEQs values close to the proposed regulatory limit of PCDD/Fs. These findings highlight the need to define reporting protocols of analytical results for risk assessments and conformity evaluation.

scholarly journals Condition-Monitoring System for Identification and Representation of the Capability Diagram Limits for Multiple Synchronous Generators in a Hydro Power-Plant

Energies ◽  
2020 ◽  
Vol 13 (15) ◽  
pp. 3800
Author(s):  
Boris Glavan ◽  
Zlatko Hanić ◽  
Marinko Kovačić ◽  
Mario Vražić
Keyword(s):  
Power Plant ◽  
Monitoring System ◽  
Condition Monitoring ◽  
Synchronous Generator ◽  
Computationally Efficient ◽  
Synchronous Generators ◽  
Hydro Power ◽  
Automation And Control ◽  
Condition Monitoring System ◽  
And Control

This paper presents an experience in the design and implementation of the condition-monitoring system for the synchronous generators whose primary purpose is to record data for the identification of the capability limits of the P–Q diagram of three generators in hydro power-plant. Paper presents details about the monitoring system, the underlying theory of the identification of the synchronous generator model with a focus on the calculation of the capability limits in the P–Q diagram. Furthermore, a computationally efficient method for the representation of capability limits suitable for the implementation within the industrial automation and control system of the power-plant is described in detail. Finally, the capability diagrams for three generators were implemented in the power-plant supervisory control and data acquisition system (SCADA) system.

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