Abstract: A protection apparatus detects and reduces overpressure in a fluid pipeline. First and second pipeline valves are connected in series along the pipeline and are independently switchable between open and closed positions. A pressure transducer determines the fluid pressure in the pipeline at a point intermediate the first and second pipeline valves. A bypass line has a first end connected to the pipeline between the input end and the first pipeline valve and a second end connected to the pipeline between the first and second pipeline valves. A bypass valve is connected along the bypass line. A vent line is connected to the bypass line between the bypass valve and the second end of the bypass line. A vent valve is connected along the vent line.