Grid-Tie Inverters; Residential / Light Commercial
utility grid interactive power
A grid-tied inverter is an electronic device that converts direct current (DC) power from a solar array into alternating current (AC) power. If you plan to invest in solar for your home or business to generate your own electricity, you will need at least one grid tie inverter and in many cases more than one.
Enphase Grid-Tie Microinverter System
Enphase provides one of the most advanced inverter technology for solar systems today. A Micro inverter converts the DC output from a single solar panel into utility AC electricity. and is meant to be located near the panel. The Enphase Micro inverter System simplifies design and installation by alleviating string-sizing constraints, and it optimizes the energy harvest of each solar panel through independent maximum power point tracking (MPPT). An Enphase System consists of Micro inverters, Engage trunk cables (M215), the Envoy Communications Gateway, and the web-based Enlighten monitoring and analysis service.
|Microinverter||Part Number||Max Panel Watts||Output Voltage||Type||Price|
|S280-60-LL-2-US||3210205||325 Watts* (STC)||240 VAC||Grid Tie|
|M215-60-2LL-S22-IG||3210196||260 Watts (STC)||240 VAC||Grid Tie||Discontinued by Enphase|
|M250-60-2LL-S22||3210194||300 Watts* (STC)||240 VAC||Grid Tie||Discontinued by Enphase|
Best Practice: Center-feed the branch circuit to minimize voltage rise in a fully-populated branch. This practice greatly reduces the voltage rise as compared with an end-fed branch. To center-feed a branch, divide the circuit into two sub-branch circuits protected by a single overcurrent protection device (OCPD).
SolarEdge Distributed MPPT Grid-Tie Inverter System
SolarEdge provides an end-to-end distributed solar power harvesting and PV monitoring solution, maximizing the power generation of residential and commercial system installations by up to 25%, for a faster return on investment. System owners enjoy the benefits of SolarEdge solutions which allow maximum power production through module-level MPPT, optimal roof utilization through constraint free design and enhanced maintenance and accurate trouble shooting through module-level monitoring. Another benefit is the guaranteed automatic DC shutdown for installers, maintenance personnel and firefighters through the unique SafeDC™ mechanism. Founded in 2006, SolarEdge established the DC power optimizer segment and is leading it with over 70% market share. By 2013, SolarEdge has shipped over 2,000,000 power optimizers to more than 45 countries worldwide.
|SolarEdge Inverter||Part Number||Max Panel Watts||Output Voltage||Type||Price|
|SE3800A-US-U||3100468||3,840 Watts (STC)||240 VAC||Grid Tie|
|SE5000A-US-U||3100469||6,250 Watts (STC)||240 VAC||Grid Tie|
|SE6000A-US-U||3100470||7,500 Watts (STC)||240 VAC||Grid Tie|
|SE7600A-US-U||3100493||9,600 Watts (STC)||240 VAC||Grid Tie|
|SE10000A-US-U||3100494||12,400 Watts (STC)||240 VAC||Grid Tie|
|SE11400A-US-U||3100495||14,400 Watts (STC)||240 VAC||Grid Tie|
Inverter must be paired with appropriate number of "P" power optimizers (1 Optimizer Per Solar Panel) and PV cable to be compliant with NEC 690.35(D) for Ungrounded PV Power Systems.
Locating your inverter. - We all fade in the heat and inverters are not any different. Inverters should be located in shady and well ventilated areas for cooling out of direct sunlight. Electrical equipment loses efficiency in direct sunlight and areas with limited ventilation.
• Off-Grid – Utility Grid Power is not available for use.
• On-Grid – Utility Grid power is available for use. Does not imply the ability to sell power back to the utility grid.
• Grid-tie, Grid-interactive, Grid-intertie, Bimodal – Utility Grid Power is available for use and the system is capable of returning (selling) electricity back to the utility grid.
SMA Grid-Tied Inverters With Stand Alone Secure Power Supply Capability
Daytime power when the grid goes down without batteries. The Sunny Boy 3000TL-US / 4000TL-US / 5000TL-US represents the next step in performance for UL certified inverters. One of many unique features of the TL-US residential series is its innovative Secure Power Supply ability. With most grid-tied inverters, when the grid goes down, so does the solar-powered home. SMA’s solution provides daytime energy to a dedicated power outlet during prolonged grid outages, providing homeowners with access to power as long as the sun shines. UL Certified, 10 Year Inverter Warranty Standard, 20 Year Available.
|SMA Secure Power Inverters||Part Number||Maximum DC Power||Output Voltage||Type||Price|
|SMA SB3000TLUS||3100441||3200 Watts||240 VAC||Grid-Tied|
|SMA SB4000TLUS||3100442||4200 Watts||240 VAC||Grid-Tied|
|SMA SB5000TLUS||3100443||5300 Watts||240 VAC||Grid-Tied|
|SMA SB6000TLUS||3100502||6300 Watts||240 VAC||Grid-Tied|
Grid Tie Inverters Enphase, SMA, Fronius and SolarEdge residential and light commercial applications.
Grid-tie inverters is an innovative concept in solar energy technology that can help today's homeowner offset high energy costs while protecting the environment. These devices differ from the stand-alone solar inverters that many homeowners use to generate their own electricity in that they tie in to the utility power grid, making it possible for energy to flow in both directions (i.e. to the customer and back out to the grid). Thus, grid-tied solar inverters don't limit the power generated by the system to the homeowner's exclusive use, but rather, by allowing users to reroute unused power back to the grid, they enable consumers to sell that power back to the utility company. This revolutionary concept is the means by which solar technology is putting unprecedented power into the hands of the consumer, in more ways than one.
How Grid-Tied Solar Inverters Work and What They Do.
Grid-tie inverters are the commonly referred to as the brains of a solar system. A photovoltaic module (solar panel) converts sunlight into electricity, using semiconductors that react to the photons in the light. Grid tie inverter systems convert direct current (DC) to alternating current (AC), making the DC energy delivered by solar panels compatible with the rest of the utility grid. These systems work by using sophisticated tracking technology that senses and adjusts the system's voltage as needed to ensure that it matches the grid's AC output voltage, thereby enabling the surplus electricity to flow back to the grid. Without this technology, the power would only be able to flow in one direction: from grid to customer. With it, the vital electricity flows from grid to customer, with the unused power flowing back to the grid again. That way, when the customer's system generates less electricity than needed, the system draws enough power from the utility grid to make up the difference, and when the system generates more power than needed, the excess is diverted back to the grid.
When a grid-tied inverter wakes up in the morning by detecting a minimum voltage output from a solar array, it then looks to the utility grid to see if it can detect electricity. If it detects the power from the grid, it then looks at the frequency of the AC utility electricity to see if it is pure sine wave (60 Hz) + - a very narrow parameter. If "all is well", the inverter then turns on and begins converting power from the solar panels and exports any excess power produced in the home onto the public utility grid.
"Power" to the People
Like many other aspects of modern technology, the grid tie inverter lets the consumer play a much more significant role in, today's marketplace. In addition to allowing homeowners to generate electricity for private use (an innovative enough concept in itself), the inverter also allows the consumer to benefit from the energy that exceeds the customer's own immediate requirements. This incentive has encouraged many homeowners to consider solar power, lessening their individual and collective burden on the environment, conserving the earth's dwindling natural resources, and helping to meet our country's growing energy needs.
Spinning the Meter Backwards
The capacity to deliver excess power back to the utility company through the delivery grid has come to be known as "spinning the meter backwards." This phrase is an apt descriptor for the bottom-line outcome that grid-tied solar inverters provide, since they actually reduce, or eliminate, the amount of metered power the consumer must purchase from the utility company. Yet, spinning the meter backwards only goes so far, since it can only be used to offset the cost of electricity actually used by the customer. While the utility company is required by law to purchase the excess electricity generated by a grid-tied solar inverter system, once the amount of energy sold to the utility company matches the amount used during a given year, there is no further financial benefit to using the system. In other words, don't allow someone to oversell you a system that will produce more than you require or it will dramatically reduce your return on investment.
How are “Grid-Tie” Inverters Different?
Most houses and commercial buildings that have a solar array as a source of electricity are also connected to their local power grid. When the electricity demand of the building is greater than what the solar array can provide, the balance can be drawn from the grid, but when the array is producing more power than is needed, the excess electricity can be sent out onto the grid to provide power for other people to use. This connection has to be managed carefully, however. The electricity has to be delivered to the grid in a form and at a power level that the utility’s system can accept. Also, if the utility suffers a power outage, the inverter has to be able to sense the blackout condition and immediately shut off the connection. This helps protect the safety of any utility workers who are trying to repair the grid and get it back into operation; a stray source of electricity can cause injury or even death to a line worker who is working on supposedly shut-down system.
New Technology, More Choices for Inverters?
Modern grid-tied inverters are designed to operate with a minimal loss of power in the transfer from the solar array to the utility grid. To maximize power production, main stream inverter companies like SMA, SolarEdge, Fronius and Enphase have designed these precisely engineered devices to feed the maximum power onto the grid. Commonly called NET metering, any excess power produced is deducted from the power consumed at night and measured each month by the utility company and reported to you in your monthly bill. Solar irradiance is dependent on temperature characteristics and the modern inverter must constantly adjust to achieve maximum power point tracker (MPPT) for climate conditions and cloud cover. To do this, inverters adjust the voltage so the system runs at its maximum power output at any given moment of the day. Additionally the inverter in most cases, records the operating data from the system which can be stored and reviewed in either real time or later by calling up the data. The newest trend in grid-tied inverters are high-frequency (HF) transformers in place of heavy coils and "H" bridge used in converting DC to AC power. High frequency transformers have lower efficiency losses and are smaller and lighter.
Changes Are Coming.
The new 2011 national electric code (NEC) is slowly being adapted by all 50 states. Section 690.11 of the 2011 National Electrical Code sets new requirements for solar systems installed on a building. These requirements apply to newly installed solar systems with a maximum voltage of 80VDC or greater. Such solar systems must be equipped with direct current (DC) arc-fault circuit protection designed into the inverter. DC arc-fault circuit protection provides a greater safety buffer against fires that may arise as a result of arcing faults in solar system components or wiring. Most of the grid-tied inverters that Blue Pacific Solar sells have this newly required arc-fault circuit protection. Check the data sheet to verify the inverter you select has this feature if your local code authority requires it. Need help? Blue Pacific Solar has System Integrators standing by to help you find the grid-tie inverter that meets your needs and budget.