Compare D.C. and A.C. transmission systems.

A comparison of d.c. and a.c. transmission is given in the table below :

Sr. No.	Point of Comparison	D.C. System	A.C. System
1.	No. of conductors	2	3 in 3 phase 3 wire system
2.	Inductive capacitive effect	It has no problem of inductance. Capacitive effect is not there.	Both factors affect regulation.
3.	Skin effect	No effect	Skin effect reduces efficiency.
4.	Voltage regulation	Better	Poor
5.	Insulation requirement	Less insulation is required.	Higher insulation is required.
6.	Corona loss	Less	Higher
7.	Transmission voltage	Voltage can't be stepped up or down.	Voltage can be easily stepped up/down by use of transformer.