There are several types of earthing, including but not limited to:
Neutral earthing - The neutral point of an electrical system is connected to earth. This is typically done in systems with multiple generators or where a neutral point is required for other reasons.
Solid earthing - The electrical system is connected to a single point on the earth. This is typically done in systems where a neutral point is not required.
High impedance earthing - The electrical system is connected to a point on the earth through a high impedance device. This is typically done in systems where a neutral point is required, but a low impedance connection would cause problems.
Resistor earthed - The electrical system is connected to a point on the earth through a resistor. This is typically done in systems where a neutral point is required, but a low impedance connection would cause problems.
Reactor earthed - The electrical system is connected to a point on the earth through a reactor. This is typically done in systems where a neutral point is required, but a low impedance connection would cause problems.
Ufer Earthing - This type of earthing is used for grounding of concrete encased electrical systems and is a combination of concrete encased electrode and a grounding electrode conductor.
These are the common types of earthing system used in electrical systems, the type of earthing used depends on the system configuration and safety requirements.