When the third season of “Orange Is the New Black” premieres Friday, you can lock up its fans and throw away the key — as long as they’ve got a computer screen and an Internet connection.

“OITNB,” as its fans shorthand it, is an original Netflix series following the lives of women serving time at Litchfield Penitentiary, a fictional upstate New York women’s prison. The central character, Piper (Taylor Schilling), is a classic blonde WASP busted for toting drug money after her street-smart former girlfriend Alex (Laura Prepon) rats her out.

A preview of the first few of the 13 new episodes reveals a lighter overall tone this season, with one-line zingers galore, new guards, an intriguing new inmate or two, a bedbug infestation that forces everyone to run around in granny panties and bullet bras, and the usual strife, subterfuge and side-eye from Crazy Eyes. Boring Larry is gone, but so is fabulously loathsome abusive guard Pornstache. Still no back story, so far, on why Crazy Eyes is doing time, but we get to see Sophia (Laverne Cox) as a man.

A brief explainer for the unincarcerated, er, uninitiated: “OITNB” is adapted from a book by Piper Kerman, an upper-middle-class Smith grad who really went to prison for a year. In the hands of Jenji Kohan, the genius writer/producer/director behind “Weeds,” the show not only breaks ground in character development for women of color, who are underrepresented on television. It’s also one of the most compelling, well-written series running anywhere, be it prime-time network, pay cable or on-demand streaming. Along with “House of Cards,” “OITNB” has made Netflix a major player in original online programming, leading to new successes such as the Florida drama “Bloodline” and the Tina Fey-helmed comedy “Unbreakable Kimmy Schmidt.”

Kohan calls “OINTB” a drama and a comedy — she doesn’t think one should exist without the other. And with more than 30 regular speaking roles and a back story told in flashbacks for nearly every one, there’s plenty of both to go around.

Early critics of the series complained that it took the story of a white blonde to get the show made in the first place, but Piper is arguably the least interesting character on the show, perhaps by design. Cliques at Litchfield divide along racial and cultural lines — African-American, Latina, white-trash meth heads — and do battle verbally and physically.

Suzanne, aka Crazy Eyes (Uzo Aduba, who won an Emmy last season), barrels her way in and out of sanity. Doggett, aka Pennsatucky (Taryn Manning), has had more abortions than she has good teeth, and has softened her avenging evangelical angel act. Red (Kate Mulgrew), a formidable Russian chef, has been banished from her domain, the prison kitchen, which has been taken over by Gloria (Selenis Leyva) and her “Spanish Harlem” Latina gang.

Santeria and segregation

This season, Gloria steps up her Santeria rituals, which Leyva calls “Catholic plus.”

“I told a writer in the first season that I dabble in it, and suddenly it was written into my character,” Leyva said in an interview this week. “You have to watch what you say to the writers.”

Leyva never expected the show to become such a cult phenomenon, she said: “I knew it was good; I just didn’t know who would watch. Turns out a whole lot of people see themselves in these women, because we don’t focus on just one person like most shows. The beauty of it is we can keep delving deeper into these women we think we already know and it could go on forever.”

While the Latina women get plenty of screen time, Leyva said, she doesn’t feel that they have been acknowledged in the media as much as some of the prison’s other groups.

“Our story is so layered, you get to see who we really are,” she said. “The way we separate into groups, that’s real life, but it’s interesting to see how even the media segregates us, like putting all the black women on a magazine cover together. The Latinas haven’t been on a cover.”

What’s in store for Gloria in the second half of the season? Leyva only offered this teaser: “The journey she goes on got really uncomfortable. But it’s going to be a great conversation.”

Character connection

Many an “OITNB” follower is guilty of binge-watching. Not Yael Stone.

“I can’t do more than three episodes at a time of anything,” said Stone, who plays sweet, scrappy and delusional Morello, imprisoned for stalking a man she claimed was her fiancé. This season Morello has a different fantasy keeping hope alive, as well as a new way to pursue love interests.

“I feel a personal connection to her; she’s optimistic and hopeful,” said Stone, an Aussie who affects a not-quite-placeable broad-voweled East Coast accent to play Morello. “Most of the people on the show really love their characters, because they feel like real people. How connected we feel to them plays a huge role in its success, because the audience feels it, too.”

With so may big personalities jockeying for screen time, surely some behind-the-scenes tension flares up now and then?

“You’d be surprised,” Stone said. “It sounds idealistic, so Baby-Sitters Club, but there is a great deal of respect, love and joy on set, across the board.”

Added Leyva, “Jenji doesn’t allow any BS on the set.”

Another giant step forward is the way the show pictures all types of bodies in various states of undress, unself-consciously.

“We’ve got all shapes, sizes, ages and colors,” Stone said. “It’s been very liberating.”