A protection and control system which is capable of surely updating a program without a program update by an operator and without deactivating a power system is provided. A protection and control device 1 includes an update accepting unit 1c that determines whether or not to accept the update of the program from a managing server 3, and an updating processing unit 1d that receives an updating program and that updates the program. The managing server 3 includes an update determining unit 3c that determines whether or not a supplied update program is for updating the program of the predetermined protection and control device 1, a transmitting unit 3b that transmits an update notification to the protection and control device 1 on which the program to be updated is loaded, and a receiving unit 3a that receives a reply to the update notification from the protection and control device.