Application of STATCOM to an Industrial Distribution System Connected to a Weak Utility System

The application of STATCOM or STATCON is common in transmission systems-the device has a capability of P-Q control in four quadrants. DSTATCOM (for distribution systems) and dynamic voltage regulator are somewhat synonymous. This paper describes a unique distribution system with three in-plant generators and an interconnection to a weak utility system at 44 kV; the three-phase short-circuit level at the utility source is only 151.7 MVA. So long as the generators are in operation, the power factor at the utility interconnection can be maintained close to unity and the voltage profiles in the system are acceptable-a total of 64 MW of load is served from 3-13.8-kV interconnected bus system. To control the voltage dips on loss of generation, 31 Mvar of capacitor filters (as the distribution system has considerable drive system loads and harmonic analysis study is conducted) are installed, yet the voltage dip can exceed 25%. A STATCOM can restore the voltage in one-half cycle. The STATCOM is also briefly compared with other technologies like TCR and TSC.