Capstone Turbine Corporation • 16640 Stagg Street • Van Nuys • CA 91406 • USA
Installation Guide: Capstone C1000S/C800S/C600S with C1000 Series Controller
480064 Rev C (December 2018) Page 105 of 122
Capstone reserves the right to change or modify, without notice, the design, specifications, and/or contents of this document without
incurring any obligation either with respect to equipment previously sold or in the process of construction.
7.8. Harmonics
It is important to keep harmonic levels to a minimum in any electrical installation. In addition to
potential damage to customer equipment, high harmonic loads can increase stress on EMI filters
in the microturbine, whether operating in Grid Connect or Stand Alone mode. In Stand Alone
mode, current harmonic distortion can overheat and significantly reduce the life of microturbine
batteries, IGBTs and other high power components.
7.8.1. Measuring Harmonics
It is recommended that a power quality study be performed on all installations, both for Stand
Alone and Grid Connect operation, so that potentially costly challenges associated with harmonics
can be avoided during the life of the project. A power quality study is performed using a power
quality meter, which is a tool that measures voltages and currents on a three-phase electrical
system with built-in calculations and graphing functions to explore subjects such as harmonic
distortion, inrush currents, flicker, and others. This tool is sold by a number of electrical instrument
companies, and can be rented temporarily in some parts of the world.
Voltage total harmonic distortion (THD) of 5% or greater in Grid Connect
operation, and current THD of 8% or greater in Stand Alone operation, will
damage microturbine hardware.
7.8.1.1. Grid Connect
For Grid Connect projects, the power quality meter can verify the voltage total harmonic distortion
(THD) of the existing site, which should be below 5%, as specified by IEEE 519. If the voltage
THD exceeds 5%, this will damage the microturbine hardware. High voltage harmonics can be
caused by large non-linear loads on the same circuit, which may not even be located in the same
facility, or by weak grids. Support from the local utility may be required.
7.8.1.2. Stand Alone
For Stand Alone projects, the power quality meter can verify the current THD of the existing site,
which should be below 8% to meet Capstone requirements. If the current THD exceeds 8%, this
will damage the microturbine hardware. In addition, the high current THD will lead to degradation
in site power quality (voltage THD), due to a positive feedback effect on the inverter controls,
which may be perceived as voltage “flicker”. High current harmonics are created by switch mode
power electronics devices such as:
Variable Frequency Drives (VFD) / Variable Speed Drives (VSD)
Uninterruptible Power Supplies (UPS)
Heaters with thyristors, or Silicone Controlled Rectifiers (SCR)
Fluorescent ballasts and sodium lamps
To Next Page
Loading...
Need help?
General