Promising chemical barrier substance applied to ichthyofauna in hydroelectric plants

In hydroelectric plants, there are, on a regular or untimely basis, shutdowns of the generating units in order to carry out some maneuvers for tests and mechanical maintenance. The low operating flow increases the probability of accumulation of ichthyofauna in the draft tube. As a result, the variables that determine the quality of water can change, which requires a broad and coordinated human effort to rescue trapped fish. In addition to the risks related to work safety, there are large economic liabilities as a result of the downtime of the generating units. To minimize this problem, it is necessary to improve techniques for repelling fish from risk areas. The detection of chemical substances in water is one of the most efficient methods of communication between fish. Thus, this study presents a brief review of alarm substances, which are released by the fish epidermis as a sign of defensive response to a dangerous situation and are promising for use as a chemical barrier in the hydroelectric sector.

Availability Projections of Hydroelectric Power Plants through Monte Carlo Simulation

The present work proposes a Monte Carlo Simulation (MCS) to obtain availability projections for Hydroelectric Power Plants (HPP), based mainly on regulatory aspects involving the Availability Factor (AFA). The main purpose of the simulation is to generate scenarios to obtain statistics for risk analysis and decision-making in relation to the HPP. The proposed methodology consists of two steps, firstly, the optimization of the maintenance schedule of the hydroelectric plant is carried out, in order to allocate the mandatory maintenance in the simulation horizon. Then, for the MCS, scenarios of forced shutdowns of the Generating Units (GU) will be generated, which directly influence the operation and, consequently, the availability of the HPP. The scenarios will be inserted into an operation optimization model, which considers the impact of forced shutdown samples on the MCS. The proposed modeling was applied using real data from the Santo Antônio HPP, which is one of the largest hydroelectric plants in Brazil.

Hydro-generators fault diagnosis with short-time-wavelet-entropy and variational auto-encoder

The prognosis and health management (PHM) of hydroelectric plants are full of difficulties caused by the complexity of the hydro-generators where each machine is different and almost unique. At industrial level, several tools are used to monitor the generator condition. Among these tools, the measurement of magnetic stray flux is one which is gaining interest. This measurement is generally based on an inductive sensor and mainly mounted near the stator. The main advantages of the magnetic stray flux are the non-invasive nature and the simplicity of its implementation. In this work, the discrete wavelet transform (DWT) is used to decompose the stray flux signal. Short-Time-Wavelet-Entropy (STWE) is then applied to extract the features from the sub-bands. Finally, a variational auto-encoder (VAE) is used in an unsupervised learning process to structure the STWE signatures of more than 400 stray flux measurement collected on real hydroelectric plants. The obtained results show that the VAE has well captured the features from the wavelet entropy (WE) signatures. An analysis of the resulting latent space shows a strong correlation between a given trajectory in the reduced space and an increase of the WE.

Generating Electricity from Micro-hydro Power Stations to Feed the Isolated Areas of the National Network

The construction of small-hydro power stations does not require high technologies, but needs to provide a river or stream water is smooth. Through the establishment of small dams on the stream can control the amount of water necessary to rotate the water turbine, which in turn converts the potential energy of water into kinetic energy. Through the transfer of kinetic energy of rotation of the turbine to the generator can convert this energy into electrical energy. The idea of ​​our plan of research for electrical energy from the power of water using small- hydroelectric plants, which can be built on small rivers, streams, and through the construction of small dams to control the amount of water. Electrical energy derived from small- hydroelectric plants could help feed the electrical loads to areas isolated from the national grid and can be linked with the national grid to add additional electric power.

Recent hydrological droughts in Brazil and their impacts on energy security

Brazil is heavily reliant on water resources. Hydroelectric plants generate about 64% of all electricity consumed. To increase yield capacity, a 2050 expansion is also planned. 78% of water used is for agriculture (irrigation and livestock), 9% for industry, and 9.1% for urban supply. However, the country has endured the worst droughts in recorded history over the last two decades, resulting in severe socioeconomic and environmental impacts. The purpose of this study was to determine the current state of knowledge regarding hydrological drought patterns, hydrometeorological factors, and their effects on the country’s hydroelectric power plants. Droughts have occurred in most of Brazil’s regions since 2014/15, causing severe impacts in many of the basins studied. Now that most hydroelectric power plants are operating at a fraction of their total capacity, the country’s hydroelectric generation is been impacted.

Changes in the hydro-sedimentary balance: Impacts of the use of a borrow pit in a low-order stream

Construction of dams for hydroelectric power requires significant quantities of soil and rock, which are often extracted in borrow pits from adjacent regions. Although the effects of dams on stream processes has received significant attention, the effects of borrow pits has not. The main objective of this study was to analyze the geomorphological and sedimentological aspects of two second-order streams, one of which was directly affected by the borrow pit located upstream of its source (Pedra Branca stream). Flow rates were measured and cross-sections of 600m stretches in both streams were monitored over a hydrological year. At the same time, sediments from the bed of the channels and soils on their banks had their physical and chemical characteristics evaluated. Streams sediments differed in their chemical and organic matter composition. The mean particle size of the sediment particles was different between the reference and degraded streams. The water flow was very similar to both streams, only varying along the seasonal seasons. However, the fluvial channels presented great geomorphological differentiation, mainly downstream, due to the location of the Pedra Branca stream and its proximity to the borrow pit. Despite the great importance for the production of clean electric energy, the construction of hydroelectric plants promotes persistent impacts that affect structural and functional aspects of the adjacent aquatic habitats. Borrow pits used for the construction of projects become large sources of sediment for aquatic environments, affecting the drainage network of the hydrographic basin and the balance of river erosion, transport and deposition processes. The results show the need to review the intervention protocols in borrow pits and the environmental legislation that regulates their rehabilitation.