GE B30 Instruction Manual page 368

SYSTEM SETUP
The Multiplier and Adder settings only affect the curve portion of the characteristic and not the MRT and HCT
settings. The HCT settings override the MRT settings for multiples of pickup greater than the HCT ratio.
5
5.5.6.4 Example
A composite curve can be created from the GE_111 standard with MRT = 200 ms and HCT initially disabled and then
enabled at eight times pickup with an operating time of 30 ms. At approximately four times pickup, the curve operating
time is equal to the MRT and from then onwards the operating time remains at 200 ms.
With the HCT feature enabled, the operating time reduces to 30 ms for pickup multiples exceeding eight times pickup.
5-160
Figure 5-75: Recloser curve initialization
Figure 5-76: Composite recloser curve with HCT disabled
CHAPTER 5: SETTINGS
B30 BUS DIFFERENTIAL SYSTEM – INSTRUCTION MANUAL