A year after NK Jemisin became the first black person to win the Hugo award for best novel, the African American author has landed the prestigious science fiction prize for the second year running.

Jemisin was announced as the winner of the best novel Hugo at Worldcon in Helsinki on Friday. She took the prize, which is voted for by fans, for The Obelisk Gate, the follow-up to her Hugo award-winning novel The Fifth Season. The series is set in a world that is constantly threatened by seismic activity, and where the mutants who can control the environment are oppressed by humans. The New York Times called Jemisin’s writing in the series “intricate and extraordinary”.

Hugos administrator Nicholas Whyte said that 3,319 people voted in this year’s award, the third-highest vote total ever and the highest participation in the Hugos for a Worldcon outside the US or UK. “There’s been a very high level of genuine engagement and thoughtful participation,” said Whyte. “People can read into that what they like.”

The last two years of the Hugos have been plagued by block-voting campaigns from conservative lobbies calling themselves the Sad Puppies, and the more politically extreme Rabid Puppies. The two factions were out to combat a perceived tendency to reward books described by one disgruntled writer as “niche, academic, overtly to the left in ideology and flavour and ultimately lacking what might best be called visceral, gut-level, swashbuckling fun”. In 2015, this led to “no award” beating the Puppies’ slate of nominees in an unprecedented five categories, in order to avoid giving prizes to the group’s nominations. In 2016, candidates put forward by the so-called Puppies also dominated the ballots, but only two “no awards” were given.

This year, there was not a single “no award” given. On a roster of predominantly female winners, Seanan McGuire’s Every Heart a Doorway took the best novella gong, Ursula Vernon’s The Tomato Thief won best novelette, and Amal El-Mohtar’s Seasons of Glass and Iron won best short story. Revered fantasy author Ursula K Le Guin took the best related work Hugo for Words Are My Matter, a collection of her writing about life and books spanning the last 16 years, while Lois McMaster Bujold won a new award for best series, for her long-running Vorkosigan Saga. The John W Campbell award for best new writer was taken by Ada Palmer.

“This is the first time that the same author has won two years running since Lois McMaster Bujold in 1991 and 1992, a quarter of a century ago; and of course Bujold’s continuing appeal was confirmed by the Vorkosigan saga winning the new best series category,” said Whyte of Jemisin’s win. “This is a super set of results ... which demonstrate that SF is thriving and diverse.”

When Jemisin won the Hugo last year, she said that when she set out to write The Fifth Season, she had thought that no one would want to read it, and then when it was nominated for a Hugo, she had wondered who might vote for it.

She wrote on her website: “I wondered how many of my fellow SFF fans, in a year headlined by reactionary pushback against the presence and performance of people like me in the genre, would choose to vote for the story of a fortysomething big-boned dreadlocked woman of colour waging an epic struggle against the forces of oppression.”

“But I forgot: only a small number of ideologues have attempted to game the Hugo awards. That small number can easily be overwhelmed, their regressive clamour stilled, if the rest of SFF fandom simply stands up to be counted. Stands up to say that yes, they do want literary innovation, and realistic representation. Stands up to say that yes, they do just want to read good stories – but what makes a story good is skill, and audacity and the ability to consider the future clearly rather than through the foggy lenses of nostalgia and privilege.”

The Hugos have been running since the 1950s and have been won by authors including Isaac Asimov, Robert A Heinlein and Neil Gaiman.

Hugo winners 2017

Best novel
The Obelisk Gate by NK Jemisin (Orbit Books)

Best novella
Every Heart a Doorway by Seanan McGuire (Tor.com publishing)

Best novelette
The Tomato Thief by Ursula Vernon (Apex Magazine, January 2016)

Best short story
Seasons of Glass and Iron, by Amal El-Mohtar (The Starlit Wood: New Fairy Tales, Saga Press)

Best related work
Words Are My Matter: Writings About Life and Books, 2000-2016 by Ursula K Le Guin (Small Beer)

Best graphic story
Monstress, Volume 1: Awakening, written by Marjorie Liu, illustrated by Sana Takeda (Image)

Best dramatic presentation (long form)
Arrival, screenplay by Eric Heisserer based on a short story by Ted Chiang, directed by Denis Villeneuve

Best dramatic presentation (short form)
The Expanse: Leviathan Wakes, written by Mark Fergus and Hawk Ostby, directed by Terry McDonough (SyFy)

Best series
The Vorkosigan Saga by Lois McMaster Bujold (Baen)

John W Campbell award for best new writer
Ada Palmer