The first one is about the term process bus. IEC 61850 does not use that term anymore (in fact it never did in a standard document). With the concept of IEC 61850, any communication architecture in a substation is possible including a global network. What today is considered to be a process bus is in the most cases a solution that uses communication according to IEC 61850-9-2 to transmit sampled values of the analog waveform from the CT/VT to the IEDs. In some cases, it may include a digital interface down to the circuit breaker that transmits trip signals using GOOSE messaging.