Renewable Energy and Current Transformers in Solar and Wind Power Systems
Renewable energy is the topic of our time, as untenable changes to global weather systems further underline the dangerous impacts of human industry on world climate. Climate change is, at this point, an undisputable fact, with the burning of fossil fuels chiefly to blame for rising temperatures and sea levels alike.
Renewable energy has been part of the conversation for decades but is taking center stage as meaningful alternatives to oil and gas become more and more important. Wind and solar are the most promising forms of renewable energy, with facilities already up and running across the US and around the world. But, just as with regular electrical plants, these facilities require close and precise measurement to succeed.
The Need for Current Measurement in Renewable Energy Systems
Current measurement is a vital aspect of energy production and distribution, regardless the system used to generate said energy. It is important for engineers to measure and monitor the energy produced in a system, not just as a means of understanding the capabilities of the system but also as a means of protecting the system.
As a basic principle of electricity, current is an essential measurement to track; direct current, or DC, measured in amperes, is one part of an equation used to calculate the power produced by, or passing through, a system. Power in Watts (W) is given by current (I) multiplied by voltage (V). Tracking this ensures that the system can be kept running within operational parameters, while also tracking energy offset and the efficiency capabilities of the system.
Introduction to Current Transformers (CTs)
But measuring current is easier said than done. In order to accurately measure current in a system, the measuring apparatus needs to be placed in series with the system – as opposed to voltage, which is measured across a system in parallel. This introduces logistical issues at all levels, but with particular regard to high-current systems as with power generation. Not only does placing measuring apparatus in series with a power-generating system impede the flow of electricity, but it also adds a point of failure to the system.
The solution is an elegant one, in the form of current transformers. Transformers are electrical components that use the principle of inductance to replicate an electrical impulse, flow or signal that is isolated from its source. Two sets of wire windings are wrapped around a metal core in close proximity to one another; the electromagnetic field induced by the flow of electricity through one coil in turn induces an electrical flow in the other.
Application of CTs in Solar and Wind Power Systems
These can be used to ‘trade’ current for voltage, by increasing or decreasing the number of windings in one coil relative to another. This, combined with the isolation of the generated electricity from the initial flow, makes current transformers ideal components for measuring current flow. Current can be ‘stepped down’ and a smaller current generated that can in turn be measured safely by an ammeter. This enables the ongoing monitoring of current flow without disruption of the system.