Later, with technological advancements, 220V AC generators were developed. Therefore, European countries that later established their power grids directly adopted the then-most advanced 220V-240V technology. Countries already using 110V-127V, however, found the cost of completely replacing their power systems with 220V too high and have continued using it to this day. Objectively speaking, a 220V system is more economical than a 110V system, and it can directly separate 220V single-phase power from the 380V power supply for residential use without a transformer, making it more advanced than 110V.
The UK initially used 240V, but later changed to 230V to align with the EU standard. Most Commonwealth countries and British overseas territories adopted this standard; for example, Australia, New Zealand, India, and Nigeria use 240V, while Malaysia, Singapore, and Pakistan use 230V. However, there are exceptions. For instance, Canada and Jamaica use 110V due to US influence; Hong Kong uses 220V because it relies on power from mainland China. Many Middle Eastern countries were under British influence in the late 19th and early 20th centuries, and therefore mostly adopted the British standard, around 230-240V.
Germany uses 230V, and as a result, the voltage across almost the entire European continent is around 220V-230V. Most of their former colonies in Asia, Africa, and Latin America also use this standard. Former Soviet republics mostly use 220V (Russia is gradually switching to 230V), and China, Mongolia, and Vietnam also use 220V because they follow the Soviet standard.
Photovoltaic grid-connected inverters have a wide output voltage range, generally compatible with 220V to 240V, but not with 110V.
my country's three-phase power grid structures include IT, TT, TN-C, and TN-S. Among them, TT, TN-C, and TN-S require a neutral wire, while IT does not. In TN-C, the neutral and ground wires can be connected together, but in TN-S, they cannot be connected together and must not be connected incorrectly.
TN-C system, three-phase four-wire, neutral and ground wires are grounded together.
TN-S system, three-phase five-wire, with separate neutral and ground wires.
TT system, three-phase four-wire, neutral and ground wires are separate, ground wire is connected to the equipment casing.
IT systems use a three-phase, three-wire system, with separate neutral and ground wires; the ground wire is connected to the equipment casing.
my country's industrial and commercial power grids generally use three-phase five-wire TN-S systems or three-phase three-wire IT systems. Grid-connected inverters typically output in a star-connected three-phase five-wire or delta-connected three-phase three-wire configuration. If the following faults occur when the inverter is connected to the grid (using a Growatt inverter as an example), it indicates that the inverter's output and the grid are not properly matched:
1) The inverter displays a large difference in the voltage of each phase of AC, but the voltage of each phase is basically the same when measured with a multimeter.
Cause: The power grid is a three-phase, three-wire IT system, while the inverter output is a three-phase, five-wire system, but the neutral wire is not connected, causing inaccurate AC voltage sampling. Solution: Notify Growatt after-sales service to change the inverter's output system to a three-phase, three-wire system.
2) The inverter displays "ERROR111" indicating a ground fault.
Cause: The power grid is a three-phase five-wire TN-S system; the inverter output neutral and ground wires are reversed. Solution: Disconnect the neutral and ground wires and reconnect them according to the requirements.
The United States power grid structure: The low-voltage power grid in the United States has two systems, according to the U.S. national standard (ANSI C84-1a-1980): 1. Split Phase system, voltage 120/240V; 2. Delta 3 Phase system, 480/277V and 208/120V three-phase system.
American-style home SplitPhase system, voltage 120/240V
Delta3Phase240/120V Three-Phase System
In the United States, household appliances typically operate on 110V, but most incoming electrical distribution boxes use a split-phase system, meaning they have two live wires. Three-phase voltage in the US is available in both 208V and 480V. Shenzhen Growatt Co., Ltd. has a strong presence in the US market, offering a variety of product models to suit its needs.
240VSplitPhase system
The image above shows the connection method between a single-phase inverter and the US SplitPhase system power grid. Inverter models include Growatt 1.5-3K-US, Growatt 2-3KHF–US, Growatt 3.6-5KMTL-US, Growatt 4-7.6KMTLP-US, and Growatt 8-11KMTL-US. These products have passed multiple certifications such as UL1741, UL1998, IEEE1547, CSAC222No1071-1, FCCPart15 (Class A & B), and UL1699B, and can be sold in the US and North American markets.
Connection method between a single-phase inverter and a 208V three-phase power grid in the United States
In the United States, three-phase power grids have three voltage levels: 208V, 240V, and 480V. 208V and 240V are generally used in residential systems, while industrial three-phase voltages are typically 480V/277V. Growatt offers two models compatible with 480V three-phase systems: Growatt 10-20KTL3-US and Growatt 30-40KTL3-US.
In summary, although the voltage levels in the United States are different from those in China, the inverter can still be used after some modifications. The key is to obtain UL certification in the United States.
110-120V: Suitable for the United States, Canada, Jamaica, Mexico, Cuba, Colombia, and other North American countries and regions, the Cayman Islands, Japan, Taiwan, and other regions.
230-240V: The United Kingdom and most Commonwealth member states, most British overseas territories, and most Middle Eastern countries.
220-230V: China, Russia, continental European countries, and most of their former colonies; former Soviet republics, and countries heavily influenced by the Soviet Union.
