By Lisa Richwine

LOS ANGELES, July 10 (Reuters) - A veteran actress says it is the "delicious" scripts and unvarnished realism of the female prison inmates that draw viewers to "Orange is the New Black," while the creator of "House of Cards" credits a ruthless yet vulnerable power couple for the thriller's success.

The unconventional approach to TV at Netflix Inc netted 31 Emmy nominations on Thursday, a major achievement for a company that plunged into original programming just last year.

"Thirty-one nods - not bad for the new kid on the block," said "House of Cards" star Kevin Spacey, nominated for best actor in a drama series for the second straight year.

It is still less than a third of the nominations for cable competitor Time Warner Inc's HBO, but Netflix is now nipping on the heels of networks that have been in the TV business for decades and is advancing careers for people who have been around a long time.

"I have never been nominated for an Emmy before, and I've been acting for 40 years," said Kate Mulgrew, a supporting comedy actress nominee for her role as a powerful inmate in "Orange is the New Black." "It has particular resonance for me."

Netflix made history last year when it shook up Hollywood with the first nominations in major categories for shows delivered exclusively over the Internet. Netflix took home three Emmys for "House of Cards" for its 14 nominations overall.

At that time, "Orange is the New Black," a dark prison comedy, was just gathering steam with its surprising twists and turns in season one.

When a new script arrives, Mulgrew said "my heart pounds a little faster because I know within those pages there is going to be something so unexpected, so awful, so delicious."

The relatable characters, who wear little makeup and only drab prison garb, also drive the show's appeal.

"Those are not surgically enhanced lips," Mulgrew said. "Those are not porcelain veneers. These are real women in a really challenging situation. They are trying, each of them in their own way, to survive it as well as she can. You are drawn in."

'TV SCREENS, TABLETS, OR PHONES'

The diverse cast includes the first openly transgender Emmy nominee, Laverne Cox, for her portrayal of an inmate who committed fraud to pay for a sex change procedure.

Netflix is investing in original shows to help attract new subscribers to its TV and movie streaming service. It has made a mark by releasing all episodes of a season at once, fueling binge-viewing and getting new fans, although the company does not release ratings.

Upcoming Netflix shows include "Marco Polo," an epic drama being filmed in Asia, and comedy "Grace and Frankie" starring Jane Fonda and Lily Tomlin.

Other digital outlets have joined Netflix in producing original content but have not made it to the Emmy race. Amazon.com Inc actively campaigned for nominations for its John Goodman political comedy "Alpha House" with billboards and mobile ads urging Emmy voters to recognize the show.

Beau Willimon, creator and executive producer of "House of Cards," said Netflix has "deep respect for the creative process" and allowed him, Spacey and costar Robin Wright to create "layered characters who aren't just reduced to their ambition and ruthlessness."

"They show vulnerability and humanity in ways that surprise us," Willimon said. "I think audiences have come to expect those sophisticated complex characters on their TV screens or tablets or phones." (Editing by Mary Milliken and Jonathan Oatis)