Delta Connected Banks; H-Configuration; Tapped Configuration - GE C70 Instruction Manual

CONNECTIONS OF SHUNT CAPACITOR BANKS CHAPTER 8: APPLICATION OF SETTINGS

8.2.3 Delta connected banks

Delta-connected banks are generally used only at distribution voltages and are configured with a single series group of
capacitors rated at line-to-line voltage. With only one series group of units, no overvoltage occurs across the remaining
capacitor units from the isolation of a faulted capacitor unit.

8.2.4 H-configuration

Some larger banks use an H-configuration in each phase with a current transformer connected between the two legs to
compare the current down each leg. As long as all capacitors are balanced, no current flows through the current
transformer. If a capacitor fuse operates or an element shorts, some current flows through the current transformer. This
bridge connection facilitates very sensitive protection. The H-arrangement is used on large banks with many capacitor
units in parallel.

8.2.5 Tapped configuration

Some larger banks use a tapped configuration in each phase with voltage transformers connected from the phase to
ground and from the tap to ground. As long as no fuses have opened and no elements have shorted, the ratio of these two
voltages remains constant. The ratio changes with any capacitor failure in the phase, providing sensitive protection.
8.2.6 Summary
The figure summarizes the grounded wye, ungrounded wye, delta, H-bridge, and tapped connection types for capacitor
banks.
Figure 8-4: Capacitor bank connections
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8-4 C70 CAPACITOR BANK PROTECTION AND CONTROL SYSTEM – INSTRUCTION MANUAL