SEPTEMBER 14, 2016 : AYUTTHAYA - THAILAND : Under installation of Gas Insulated switch-gear for Extra high voltage electrical power at Ayutthaya 4 substation. ( GIS ) Shutterstock Image - SEPTEMBER 14, 2016 : AYUTTHAYA - THAILAND : Under installation of Gas Insulated switch-gear for Extra high voltage electrical power at Ayutthaya 4 substation. ( GIS ) - ID: 487448824