Due to problems such as loss of loads and long time to clear the faults, when using back up protection, a dedicated busbar protection scheme is required. … Instability of the power system might be caused by case of a failure to trip during an external fault or false tripping during service of the busbar.
Why is busbar protection needed?
To maintain system stability, the primary objective of busbar protection is to limit damage and remove busbar faults before back-up line protection. A low impedance differential system used to have a relatively long operation time.
Which protection system is used for busbar?
The current differential protection scheme works on the principle of the circulating current which states that the current enters into the bus-bar is equal to the current leaving the bus-bar. The sum of the incoming and outgoing junction is equal to zero.
What is busbar protection relay?
A busbar is a strip or bar of copper, brass or aluminum that conducts electricity within a switchboard, a substation or a battery bank. … The busbar protection relay is intended for use in high-impedance-based applications within utility substations and industrial power systems.
What are the most commonly used scheme for the bus protection?
The most commonly used schemes for bus-zone protection are: 1. Backup Protection for Bus-Bars 2. Frame Leakage or Fault-Bus Protection 3. Differential Overcurrent Protection.
What are the requirements of protection of lines?
The high level factors influencing line protection include:
- The criticality of the line (in terms of load transfer and system stability),
- Fault clearing time requirements for system stability,
- Line length,
- The system feeding the line,
What is the use of bus PT?
A PT is an instrument transformer. It is used to convert the bus voltage to a safer lower value for metering and indication . It provides both isolation and scaling.
What are the two types of protection given for busbar?
18.9. 4). This type of busbar protection has two types: low-impedance biased differential protection and high-impedance differential protection, as described here.
How does bus differential protection work?
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. … During a fault, the currents do not sum to zero.
What is busbar in substation?
In electric power distribution, a busbar (also bus bar) is a metallic strip or bar, typically housed inside switchgear, panel boards, and busway enclosures for local high current power distribution.
What is low impedance busbar protection?
The low- impedance bus differential scheme typically has one set of current inputs for each phase from every set of CTs in the scheme. … A single low- impedance bus differential relay can provide protection for a single phase, two phases, or all three phases, depending on the number of relay current inputs.
How busbar is rated?
Normally bus-bar is rated in terms of current, voltage, frequency and short time current based on the application.