What is partial differential protection scheme?
Partial differential protection is used to protect the bus bar from over loading, provide the backup protection for main bus overcurrent protection and backup protection for all individual source circuits. Partial-differential Protection is a modified version of current differential protection.
What is differential protection scheme where it is used?
Differential protection schemes are mainly used for protection against phase-to-phase fault and phase to earth faults. The differential protection used for power transformers is based on Merz-Prize circulating current principle. Such types of protection are generally used for transformers of rating exceeding 2 MVA.
What is bus differential protection?
Bus differential protection is based on Kirchhoff’s current law, which states that the sum of currents entering a node is zero. A bus is treated as a node, and current measurements are taken from all terminals connected to the bus. Under normal conditions, the currents sum to zero.
What provides overcurrent protection?
Overcurrent protection devices include circuit breakers and fuses. Something as simple as a circuit breaker can protect against this damage, but if a fuse or circuit breaker doesn’t have an adequate voltage rating, it can rupture or explode while attempting to stop fault currents beyond their interrupting ratings.
What is current fault?
An overcurrent occurs when the current exceeds the rated amperage capacity of that circuit or of the connected equipment (such as an appliance) on that circuit. An overcurrent can be caused by overloading the circuit or by a short circuit, a ground fault, or an arc fault.
What is the difference between protection CT and measuring CT?
What is the difference between CT for protection and Ct for metering?.. Protection ct: It is used for protection against fault in power system and also secondary connection connected to protective relay. Metering ct: It’s measure the actual current of the system and also secondary connection connected to meters.
What is the difference between bus and line?
The lines entering a substation are lines. The bus is what the other side of the breakers are connected to. The bus is the common connection point for all the incoming lines and sources.
What is check zone in busbar protection?
Check zone is a safety precaution to avoid tripping of bus bars due to defective CT Switching relays. 19. Double bus with Check Zone – Trip Logic Trip 1 Trip 2 Trip 87-1 Trip 87-2 Trip 87-CH The TRIP command is issued only when both discriminating and check-zone system operates.