Gathering Environmental Data Concerning Very High Voltage Lines
Figure 1: Aerial Inspections Using Light Detection and Ranging Technology to Detect and Classify Objects and Measure Distances
refine our calculated data; and to help us to automatically classify right-of- way in a similar fashion from data collected from our sensors.
Storks
Eucalyptus at 3.99 m
Birds, such as storks in Portugal and other countries, are a cause of risk to electrical lines due to possible collisions (which is also a risk to the bird that could die of physical injury or electric shock) and also due to their highly corrosive droppings (notice the white zones over the steel tower painted in red in Figure 2). We want to sustain bird life while keeping our lines safe. For that reason, Transmission System Operators such as REN in Portugal install special platforms on towers where the birds can build their nests in safer places (see Figure 2, left). Nevertheless, there are critical high-density bird population areas, where such platforms (and bird diverter devices) are not sufficient, and nests are built in more dangerous areas for exploration (see Figure 2, right). In these cases, maintenance is necessary to move some nests. It is thus convenient to record existing tower nests (and ideally, each exact location on the tower and whether it is occupied or not). This is important not only for the tower itself and its spans, but also to calculate local density of bird populations and verify their evolution.
Figure 2: Stork Nests in Towers
We currently register the total number of nests on each tower based on human visual inspection, but work in progress will lead to automatic processing of inspection video images in the near future.
Temperature
We register air temperatures in the territory, from the available data, mainly for historical value, but to verify, for instance, hotter regions where fires may more easily occur. The Portuguese meteorological institute have provided us with daily temperatures (minimum, maximum and average) for district capitals for the past 25 years. In addition, the grid operator has received available temperatures registered in substations every 15 minutes, for the past 10 years. We recorded all these data in the environment database.
registers minimal distances at span level, and classifies anomalies at three different levels of risk: most severe, exceeding legal regulations and requiring immediate intervention; requiring maintenance in the short term; and including a long-term maintenance schedule. With the aid of automatic and real-time data processing tools, objects are classified as vegetation, buildings or others. Together with human validation and analysis, the right-of-way is classified as rural, urban or mixed and dominant vegetation species and growth rate (this also applies to
Lightning is a major concern to grid operators since it is hard to predict and a single strike may easily cause severe damage to a line or nearby.
historical data) are identified and registered to classify land use.5 Additionally, we have access to more detailed, yet less frequently updated, surveyors’ data from the National Geographic Institute of Portugal (IGP) regarding right-of-way, which can be used in two ways: to validate and
72 Forest Fires
Forest fires, also known as wildfires, occurring under a line will most probably require the operator to take it out of service. It is thus important to estimate the probability of fire occurrence, which will benefit from historical data. From the same meteorological source, we possess daily values (on a risk scale of 1 to 5) based on observed fires, for each municipality.
Pollution
Pollution affects mainly insulators. Composites reduce sensitivity to pollution almost to a minimum – other insulators are especially critical if located in polluted areas. Pollution data is thus important in assessing the risk of lines with such insulators, to determine when to maintain them and to more easily decide where to install composites.
The grid operator already had a rough estimate of the kind of pollution (industrial, salt, dust, birds, others) each tower was subject to, qualitatively measuring it when present as light, medium or strong. Maintenance information concerning washing of dirty insulators was also available and we registered its location (towers) and dates, thus being able to determine critical areas, inferring pollution zones based on its effects, and its level based on its frequency.
MODERN ENERGY REVIEW – VOLUME 4 ISSUE 1
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