Method for operating an arrangement comprising at least one substation (20, 50) and at least one terminal (30-31, 60-61) connected to the substation (20, 50), wherein, during the method, the at least one terminal (30-31, 60-61) is equipped with a terminal certificate (EZ30, EZ31, EZ60-EZ61) and a corresponding private key which - enables signed data transmission, - indicates the substation (20, 50) as the certificate issuer of a root certificate, - has a signature of the substation (20, 50) and - contains a reference to a public key of the terminal (30-31, 60-61), wherein: - an electrical energy distribution arrangement is operated as the arrangement, - the substation (20, 50) forms an energy distribution substation, the terminal (30-31, 60-61) forms an electrical measuring, monitoring and/or protective device, and a control centre forms an energy distribution control centre, - after expanding the arrangement by connecting the control centre, which functions as the new root certificate authority of the arrangement as a result of the connection, to the substation (20, 50), the control centre recertifies the public key of the substation (20, 50) by creating, for the substation (20, 50), a signed certificate (RZ20, RZ50) containing the public key of the substation (20, 50), - in order to authenticate data which are transmitted or are intended to be transmitted from the at least one terminal (30-31, 60-61) to another terminal (30-31, 60-61), to the substation (20, 50) and/or to the control centre, the terminal certificate (EZ30, EZ31, EZ60-EZ61) which indicates the substation (20, 50) as the root certificate issuer is transmitted to the other terminal (30-31, 60-61), to the substation (20, 50) and/or to the control centre, and - the certificate check of the terminal certificate (EZ30, EZ31, EZ60-EZ61) in the receiver, that is to say the terminal, the substation and/or the control centre, and/or the authentication of the data signed with the corresponding private key is/are carried out on the basis of the recertified public key of the substation (20, 50). - enables signed data transmission, - indicates the substation (20, 50) as the certificate issuer of a root certificate, - has a signature of the substation (20, 50) and - contains a reference to a public key of the terminal (30-31, 60-61), - an electrical energy distribution arrangement is operated as the arrangement, - the substation (20, 50) forms an energy distribution substation, the terminal (30-31, 60-61) forms an electrical measuring, monitoring and/or protective device, and a control centre forms an energy distribution control centre, - after expanding the arrangement by connecting the control centre, which functions as the new root certificate authority of the arrangement as a result of the connection, to the substation (20, 50), the control centre recertifies the public key of the substation (20, 50) by creating, for the substation (20, 50), a signed certificate (RZ20, RZ50) containing the public key of the substation (20, 50), - in order to authenticate data which are transmitted or are intended to be transmitted from the at least one terminal (30-31, 60-61) to another terminal (30-31, 60-61), to the substation (20, 50) and/or to the control centre, the terminal certificate (EZ30, EZ31, EZ60-EZ61) which indicates the substation (20, 50) as the root certificate issuer is transmitted to the other terminal (30-31, 60-61), to the substation (20, 50) and/or to the control centre, and - the certificate check of the terminal certificate (EZ30, EZ31, EZ60-EZ61) in the receiver, that is to say the terminal, the substation and/or the control centre, and/or the authentication of the data signed with the corresponding private key is/are carried out on the basis of the recertified public key of the substation (20, 50).