8-4 C70 CAPACITOR BANK PROTECTION AND CONTROL SYSTEM – INSTRUCTION MANUALCONNECTIONS OF SHUNT CAPACITOR BANKS CHAPTER 8: APPLICATION OF SETTINGS88.2.3 Delta connected banksDelta-connected banks are generally used only at distribution voltages and are configured with a single series group ofcapacitors rated at line-to-line voltage. With only one series group of units, no overvoltage occurs across the remainingcapacitor units from the isolation of a faulted capacitor unit.8.2.4 H-configurationSome larger banks use an H-configuration in each phase with a current transformer connected between the two legs tocompare the current down each leg. As long as all capacitors are balanced, no current flows through the currenttransformer. If a capacitor fuse operates or an element shorts, some current flows through the current transformer. Thisbridge connection facilitates very sensitive protection. The H-arrangement is used on large banks with many capacitorunits in parallel.8.2.5 Tapped configurationSome larger banks use a tapped configuration in each phase with voltage transformers connected from the phase toground and from the tap to ground. As long as no fuses have opened and no elements have shorted, the ratio of these twovoltages remains constant. The ratio changes with any capacitor failure in the phase, providing sensitive protection.8.2.6 SummaryThe figure summarizes the grounded wye, ungrounded wye, delta, H-bridge, and tapped connection types for capacitorbanks.Figure 8-4: Capacitor bank connectionsGrounded wye Ungrounded wye DeltaH-bridge Tapped834756A1.CDR
