What is galvanic isolation and why is it required

What is galvanic isolation

Galvanic isolation is a complete physical separation between the input and output and it could be achieved by means of transformers with physically different primary and secondary windings. They are shielded from each other by an additional electrostatic plate to further reduce common-mode noise.

Why galvanic isolation is required

Galvanic isolation is required for electronic equipment or power device so that it could handle distortions without any problem. In this way, eventual earth fault can be monitored and corrected before it comes to a malfunction to the system. Galvanic isolation can reduce safety risks for maintenance personnel while working on the systems.

Do I need a galvanic isolator? What does galvanic isolation mean

By doing fully galvanic isolation between input and output, the highest level of protection against all kinds of distortion can be secured. If we do not use a galvanic isolator then it could create a lot of problems like damaging the equipment or the personnel who is operating the device will be affected by this. Galvanic isolation does the isolation of any equipment or power device so that during the voltage surges the equipment won’t be affected and the personnel who is operating the equipment will be safe too.

How does galvanic corrosion occur

Galvanic corrosion occurs when two dissimilar conducting materials are in electrical contact, it usually consists of two dissimilar conductors in electrical contact with each other and with a common conducting fluid. It may also occur when two similar conductors come in contact with each other via dissimilar electrolytes the former is the more common condition. Galvanic corrosion won’t happen in a mixed metal system which has a common electrolyte and which is electrically isolated, regardless of the proximity of the metals or their relative potential or size. The intensity of galvanic corrosion is affected by certain factors they are the potential difference between the metals or alloys and the nature of the environment.

What is isolation and How does a galvanic isolator work

Isolation is one of the most critical issues in process control. It is used to prevent unwanted current loops, ground loops, protection of delicate equipment and ensuring the safety of human operators when high common-mode voltages are to be expected. By the isolation, we can separate two circuits electrically and there won’t be any electron flow between the two circuits. Galvanic isolation can do the physical separation of the input and output. Galvanic isolation is of three types signal isolation, power level isolation, and capacitors as an isolator. Galvanic isolation of the measuring signals can be done with the help of isolation amplifiers. These amplifiers need an external power supply. Signal isolation can be done by optoisolator it is also known as an optocoupler or optical isolator. Optoisolator is a component that can transfer electrical signals between two isolated circuits by using light. Opto isolators can prevent high voltages from affecting the system receiving the signal. Opto isolators can withstand input to output voltages up to 10Kv and voltage transients with the speeds up to 25 kV.

Adding galvanic isolation between two systems eliminates all grounding and most surge problems. Before galvanic isolation, the two systems were sharing two grounds with the risk of current flow between them but by this, we have two fully closed ground systems without current flow between them. Galvanic isolation breaks the ground path by using air gaps, transformers, or optical devices. Galvanic isolation allows data to flow between systems but not electrical current.

Power level isolation can be done by the isolation transformer

Power level isolation by using relays

Rectifier with galvanic isolation

Advantages

  • It can provide higher immunity against distortion in input mains, transient voltage surge will be reduced
  • Reduction of harmonic current feedback to input mains
  • Higher safety while working on batteries for maintenance personal
  • It can monitor and react on earth fault in the DC bus and battery bank

Bypass with galvanic isolation

Advantages

  • Transformer can also be combined with a voltage stabilizer
  • if input and output voltages are different, a transformer can also be used for voltage adaptation
  • Neutral at the output can be grounded, regardless of upstream supply configuration, which is required according to most standards.