Method for operating an arrangement comprising at least one substation and at least one terminal (30-31, 60-61) connected to the substation , 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 as the certificate issuer of a root certificate, - has a signature of the substation 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 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 , the control centre recertifies the public key of the substation by creating, for the substation , a signed certificate (RZ20, RZ50) containing the public key of the substation , - 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 and/or to the control centre , the terminal certificate (EZ30, EZ31, EZ60-EZ61) which indicates the substation as the root certificate issuer is transmitted to the other terminal (30-31, 60-61), to the substation 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 . - enables signed data transmission, - indicates the substation as the certificate issuer of a root certificate, - has a signature of the substation 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 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 , the control centre recertifies the public key of the substation by creating, for the substation , a signed certificate (RZ20, RZ50) containing the public key of the substation , - 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 and/or to the control centre , the terminal certificate (EZ30, EZ31, EZ60-EZ61) which indicates the substation as the root certificate issuer is transmitted to the other terminal (30-31, 60-61), to the substation 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 . <EOS>