Principle of photovoltaic inverter leakage detection

Standard and detection of leakage current. According to the 7.10.2 regulation of NB32004-2013 standard, in any case where the solar inverter is connected to the AC grid and the AC breaker is turned off, the inverter should provide leak current detection.

This paper presents a transformerless inverter topology, which is capable of simultaneously solving leakage current and pulsating power issues in grid-connected photovoltaic (PV) systems. Without adding any additional components to the system, the leakage current caused by the PV-to-ground parasitic capacitance can be bypassed by introducing a .

Feed-in interruptions of this kind can be largely prevented by careful and professional system planning. In the following, we will therefore be explaining the crucial technical aspects to be taken into account in the planning phase, as well as during installation and commissioning of a PV system.

This paper mainly introduces a classification and extraction method of leakage current, and a method for suppressing leakage current. First, the two-stage BOOST+HERIC photovoltaic grid-connected circuit is used for simulation. Then, the measurement of the complete current is done on the result of the simulation.

Bypassing the parasitic capacitance of PV through using common-ground converters. This represents the most effective solution as it offers complete mitigation of the leakage current by providing a solid connection between the negative terminal photovoltaic modules and the neutral of the grid side.

Principle of photovoltaic inverter leakage detection [PDF] Chat with us

6 FAQs about [Principle of photovoltaic inverter leakage detection]

Does a solar inverter detect leakage current?

Standard and detection of leakage current According to the 7.10.2 regulation of NB32004-2013 standard, in any case where the solar inverter is connected to the AC grid and the AC breaker is turned off, the inverter should provide leak current detection.

Why does the photovoltaic system generate leakage current?

Leakage current of the photovoltaic system, which is also known as the square matrix residual current, is essentially a kind of common mode current. The cause is that there is parasitic capacitance between the photovoltaic system and the earth.

How to eliminate leakage current in solar PV array system?

There are two distinct methods to eliminate the leakage current in the solar PV array system: (i) obstruct the leakage current, (ii) reduce the variation/constant common-mode voltage. The additional diodes/switches are incorporated in the system to obstruct the leakage current by disconnecting the PV array from the grid side network.

What type of current sensor is required for photovoltaic leakage?

And it has an extremely high precision requirement, a special current sensor is required. The photovoltaic standard stipulates that for the detection of photovoltaic leakage current, Type B, that is, a current sensor capable of measuring both AC and DC leakage currents, must be used.

How can a transformerless PV inverter reduce leakage current?

Various solutions have been developed to suppress the leakage current for single-phase transformerless PV inverters [10 –36]. Most of these solutions are derived from the full-bridge inverter by adding an AC or DC decoupling circuit.

How to reduce leakage currents in single-phase PV connections?

According to the above analysis, there are mainly three directions that can be adopted to eliminate or minimize leakage currents in single-phase PV connections: Using of common-mode (CM) chokes: this represents an effective solution to mitigate the leakage current in grid-connected systems .

Principle of photovoltaic inverter leakage detection