As used in this chapter the term "public service company" shall include every corporation engaged in business as a public utility and subject to regulation as to rates and service by the utilities and transportation commission under the provisions of this title.

As used in this chapter, the term "affiliated interest" means:

Every corporation and person owning or holding directly or indirectly five percent or more of the voting securities of any public service company engaged in any intrastate business in this state;

Every corporation and person, other than those above specified, in any chain of successive ownership of five percent or more of voting securities, the chain beginning with the holder of the voting securities of such public service company;

Every corporation five percent or more of whose voting securities are owned by any person or corporation owning five percent or more of the voting securities of such public service company or by any person or corporation in any such chain of successive ownership of five percent or more of voting securities;

Every corporation or person with which the public service company has a management or service contract; and

Every person who is an officer or director of such public service company or of any corporation in any chain of successive ownership of five percent or more of voting securities.