Power company Drax gave a trading update in which it said that while market conditions continued to be challenging, with weak gas markets resulting in the continuation of weak power prices, its expectations for the full year remained unchanged.The FTSE 250 group continued to experience a strong contracted position and reported a good operational performance by its generating units.It also announced that it has extended its contracted position, including additional power sales of 3.4trn watts and 2.7trn watts for 2015 and 2016 respectively, compared to the position reported in February. Its first two converted biomass units continued to perform in line with expectations, while the third biomass unit conversion was awarded an investment contract, although this remains subject to EU State aid clearance. Both US pellet plants, which are being commissioned, have produced pellets which have been successfully processed at Drax, it added.