The pilot of the powered parachute reported that, during a biennial flight review, he descended to about 30 ft above the ground to fly an arc around a field. While over the field, the powered parachute dropped another 10 to 15 ft, and he added power to compensate before initiating a left turn. He added that, during the turn, he saw transmission wires that neither he nor the flight instructor previously noticed. He applied full power and attempted a turn to avoid the wires. Subsequently, the powered parachute struck the transmission wires and impacted terrain. The powered parachute sustained substantial damage to the fuselage. The pilot sustained serious injuries. The flight instructor reported that there were no preaccident mechanical failures or malfunctions with the powered parachute that would have precluded normal operation.