What are different kinds of inverters used in solar power plants?

Broadly, the solar inverters can be categorized in the following types: Grid Connected Inverters Grid connected inverters are simply inverters which are connected to the grid. These inverters produce a sine wave that is congruent with the AC waveform produced by the grid. They allow you to send surplus solar electricity, your system has generated back into the grid. Grid connected inverters have Anti-islanding feature which allows the inverter to realize the sudden change in system frequency, voltage, rate change of frequency, increase in kW beyond normal levels, or a change in kVAR and shut down the inverter. When the inverter shuts down your system is no longer producing electricity for the safety of the people who will be working on the grid to repair it. Grid connected inverters are sub categorized as follows: Central Inverter: These inverters are typically used for large scale projects (usually above 250kW). They are huge, have their own rooms with exhaust, etc. They are  are cheaper than string inverters & requires low maintenance due to lesser terminations on AC side. String Inverter: This is the most commonly used solar inverter for homes and business consumers. They are much lighter and resistant to harsh atmospheric conditions. String inverters are based on modularization, each PV string goes through an inverter, with maximum power tracking peak at the DC terminal, and grid-tied at the AC side. Micro Inverter: Micro-inverters are small sized inverters attached to individual solar panels. They use power point tracking,  which means essentially if […] Read more

What is an Operation & Maintenance contract?

An Operation & Maintenance contract establishes a contractual relationship between the plant owner, and the contractor of the project. It performs an essential role in the operations phase of the plant, and has a significant impact on the projects’ long-term success. Accordingly, it is a key document from the point of view of both, the Owner and the Contractor. A well drafted operation & maintenance contract can, not only bring transparency in responsibilities & activities, but also ensures in maximizing the energy generation from the plant and enabling it to function smoothly. Like this:Like Loading... Read more

What is clipping in inverters?

The DC to AC ratio (also known as the Inverter Load Ratio) is an important parameter when designing a solar project. The key driver here is the “clipping loss”. When the DC power feeding an inverter is more than the inverter’s capacity to, the resulting power is “clipped” and lost. Adding 20% extra panel capacity to your inverter is a wise choice: The main reason to oversize an inverter is to drive it to its full capacity more often. As PV modules do not consistently perform at their nominal output rating. The module output power is affected by the weather, the sun’s position during the day/different seasons, local site conditions and array orientation. In addition, module output power may decrease due to aging, soiling and shade. Oversizing the inverter is typically not a requirement, however an experienced PV system designer may choose to oversize the inverter in order to maximize the power production Secondly, additional loading of inverters offers reduction in overall cost of the system. However, in some countries, the local authorities prohibits inverter oversizing. In this case, one has to always follow the local regulations. [Source: Youtube] [Publisher: SolarQuotes] Like this:Like Loading... Read more

What is the difference between a normal inverter and grid connected inverter?

Normal inverter A normal inverter system or a UPS basically have batteries to store energy from the grid when the supply is available. When the power is cut off, the inverter takes the DC power from the batteries and converts it into AC used by the appliances. There is an automatic control in the system that intellects if the grid is not supplying power and switches the UPS or inverter into battery mode. Grid connected inverter A grid tied solar inverter, also converts DC power (produced from Solar Panel) to AC. But additionally they have built-in MPPT (Maximum Power Point Tracking) feature. As the voltage produced by Solar Panel varies depending on the temperature and obtainability of sun, MPPT allows solar inverters to draw maximum power from the solar panels. The solar inverter used for grid-connected system also comprises an anti-islanding functionality which basically means that the inverter is designed to shut down if the grid goes down, so that you won’t be inadvertently energizing the grid if a someone is working on it Like this:Like Loading... Read more

How does a grid connected inverter work?

The grid connected inverter takes the direct current and, in simplified terms, runs it through a transformer. The inverter runs the DC through two or more transistors that are rapidly turned on and off and feeding two different sides of the transformer to convert DC into AC. The grid connected inverters require reference frequency to synchronize with the grid (e.g. 50 or 60 Hz) using a local oscillator and limit the voltage to no higher than the grid voltage. The power produced is fed into your house/ office electrical panel and provides power for all needs.  The excess power automatically flows out to the grid, spinning meter backwards. Grid-tie inverters are also designed to quickly disconnect from the grid if the utility grid goes down to prevent the energy it transfers to the grid from harming any line workers who are fixing the line issues. This feature is known as Anti-Islanding.   Like this:Like Loading... Read more

What are the points to keep in mind while selecting a grid connected inverter?

Things to check before finalizing the grid connected inverter for your system: Warranty: Compare the warranties offered with solar inverters. Most of the manufacturers offers 10 years of warranty with annual maintenance charges . Also, check whether the manufacturer offers onsite services, years of establishment, no. of inverters sold & response time in case of technical faults. Peak Efficiency This is the specific ratio of how much energy is consumed and how much energy is output. Like other appliances, a certain amount of energy is lost in the conversion of electricity from DC to AC. Most inverters operate at 95% & above efficiency, and therefore resulting in greater amounts of energy to the grid. Power Maximization (MPPT) MPPT stands for Maximum Power Point Tracker. Its function is to maximize the energy available from the connected solar module arrays at any time during its operation. The voltage at which PV module can produce maximum power is called ‘maximum power point’ (or peak power voltage). Maximum power varies with solar radiation, ambient temperature and solar cell temperature. The major function of MPPT is to extract the maximum available power from PV module by making them operate at the most efficient voltage. Data logger & Online monitoring  Now-a-days inverters have data-logging feature enabling you to download information to a computer, or transmit it over Bluetooth or your Wi Fi network. With online monitoring you can check the real-time generation or periodic information about the performance of your system on your PC, smartphone etc. Like this:Like Loading... Read more