What Is a Low Voltage Ride Through?
Low voltage ride through (LVRT), low voltage transition capability, was once called "low voltage ride through". Definition: The ability of a small-scale power generation system to withstand a certain limit of the grid's low voltage without quitting operation within a certain period of time.
Low voltage ride through technology
- There are generally three types of low-voltage ride-through technologies: one is to use rotor short-circuit protection technology, the other is to introduce a new topology, and the third is to use a reasonable
- As shown in Figure 4, this structure is different from the traditional
Technical requirements for low voltage ride through
- 1.Suitable for grid-connected acceptance of photovoltaic power stations, grid-connected acceptance of wind farms, photovoltaic inverter type tests, and low-voltage ride-through detection platforms for wind turbines, including functional design, structure, and performance of main equipment and auxiliary equipment , Installation and test technical requirements.
- 1. It is required that the testing platform can simultaneously meet the low-voltage ride-through capability detection of a single wind turbine installed on-site in a wind farm, the low-voltage ride-through capability detection of photovoltaic power stations connected to the grid, and the photovoltaic inverters and wind power generators. Type test of low voltage ride-through test.
- 1. The minimum technical requirements are proposed, all technical details are not specified, and the relevant standards and specifications are not fully quoted. The supplier shall guarantee the provision of quality products that comply with this specification and industry standards.
Conditions of use for low voltage ride-through technology
- 1. Environmental conditions
- a) Outdoor ambient temperature requirements: -40 ~ 50 ;
- b) Outdoor humidity requirement: 0 ~ 90%;
- c) Altitude: 0 ~ 2000 meters (if it exceeds 2000 meters, it needs to be explained in advance).
- 2. Installation method: fixed installation inside standard shipping container.
- 3.Storage conditions
- a) Ambient temperature: 50 50 ;
- b) Relative humidity: 0 to 95%.
- 4. Working conditions
- a) Ambient temperature: -40 oC 40oC;
- b) Relative humidity 10% 90%, no condensation.
- 5. Power system conditions
- a) The maximum rated value of the grid voltage is 35kV, and the voltage operating range is 31.5kV ~ 40.5kV; at the same time, it can also meet the test detection of 10kV \ 20kV grid voltage.
- b) Grid frequency allowable range: 48 ~ 52Hz;
- c) Three-phase voltage imbalance of power grid: <= 4%;
- d) Total harmonic distortion rate of grid voltage: <= 5%.
- 6.Load conditions
- The load includes wind turbines such as direct-drive or double-fed, and its total capacity is not greater than 6.0MVA. Its control and operation need to meet the technical requirements of the country's relevant test procedures for wind power unit electrical voltage ride-through testing and photovoltaic power stations.
- The detection platform can simultaneously meet the low-voltage ride-through test of photovoltaic power stations or photovoltaic inverters under the same conditions.
- 7. Grounding resistance: <= 5.