Protective Relaying on 66(30)kv

1. 66(30)kV

1. 66(30)kV Line

1. Protective relaying on 66(30)kV power line is as follows, according to power line configuration, importance, line length etc  

(1) Power at both ends-underground single cable type

(2) Power at both ends-overhead single line type

(3) Radial single underground cable

(4) Radial single overhead line

1. Protective relaying on 66(30)kV power line is composed of single order of main protection and backup protection

(1) Main protection : Distance protection on 3

(2) Backup protection : Over-current protection

1. Protective relaying on 66(30)kV power line is applied by below table. (Details of each type are referenced by manuals from manufacturer and relays are installed by attached protective single line diagram.)
2. Measuring instruments as wattmeter, reactive volt-ampere meter, ampere meter are installed on 66(30)kV line

Protective relaying on power line

※ If cable is under 30% on composition of mixed cable & overhead power line, application of recloser must be investigated solely

1. 66(30)kV busbar

1. Protective relaying is selected by Busbar configuration
2. Protective relaying is divided into batch, separate, batch-separate mode according to the configuration of busbar, to efficiently manage the fault on busbar

[pic 1]

(1)                                           (2)

Batch mode

[pic 2]

(3)

Separate mode

[pic 3]

(4)                                                      (5)

Batch-separate mode

1. Standard of busbar protecton on 66(30) kV line is single order protection
2. CT for busbar protection

(1) There must be a specialized CT for busbar protection

(2) In voltage differential type busbar protection, each CT must use maximum current ration on same charecteristic

(3) In choosing CT for busbar protection, Saturation curve must be considered not to mal-function by external fault.

1. Standard of busbar protective relaying is as follows. (Details of each type are referenced by manuals from manufacturer and relays are installed by attached protective single line diagram.)

Protective relaying for busbar