Primary Frequency Regulation Using HVDC Terminals Controlling Voltage Dependent Loads

HVDC can provide frequency regulation during disturbances
(e.g., faults) by controlling the power flow between two
remote AC areas. While this action reduces the power deviation in
the area affected by the disturbance, it causes a power imbalance
in the other healthy AC area, leading to a frequency variation and
endangering the system stability. In this work, a HVDC primary
frequency regulation controlling voltage-dependent loads (PFRVDL)
is proposed, where the HVDC terminal in the healthy
area influences the grid voltage amplitude to shape (decreasing or
increasing) the load consumption in order to cope with the power
variation required by the fault-affected area. The PFR-VDL
extracts the needed energy for the frequency support, not from
the generators (with following frequency deviation) but from the
voltage-dependent loads in the healthy area. This work analyzes
the PFR-VDL performance, generalizing it with two possible
HVDC connection cases: Asynchronous connection with single
HVDC line, and embedded HVDC forming a parallel, hybrid
connection with HVAC. The PFR-VDL application benefits and
limitations are evaluated analytically and verified by means of
... mehr
PSCAD EMTDC simulations, and finally validated with a large
interconnected IEEE 39 bus system.