B777-200
Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument; Flight Crew Multiengine
Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Maintenance
Air Traffic Control Provided Assistance; Flight Crew Diverted; Flight Crew Landed As Precaution; Flight Crew Overcame Equipment Problem
Aircraft
We were operating flight from ZZZ to ZZZZ. The aircraft arrived from ZZZZ that day with numerous entries in the Aircraft Maintenance log book. ZZZ Maintenance worked to clear the issues (all electrical) including an engine run by the Captain and I while on the gate at ZZZ. We departed for ZZZZ within 10 min of our scheduled departure time. Approximately 2 hours into the flight we started observing several electrical issues including; flickering cabin lights; loss of all IFE's; failure to log onto CPDLC; failure of the SATCOM system; failure of all electrical door locking systems (cabin doors; boarding doors; galley; etc); and the electrical synoptic indicated the main left ac bus was without power. We were cruising at FL370. Smooth air and no mountain wave was reported. Our cruise airspeed was approximately 290K. Without notice; the airspeed jumped to 320 knots setting the overspeed warning clacker off and disconnecting the autopilot. We did not lose any altitude and the airspeed went back to our desired mach.  I'm not certain why this happened. The airplane had a lot of systems not functioning. I was buried in manuals and checklists at the time of the event. I have been in turbulence and mountain wave; experiencing plenty of airspeed fluctuations. This incident was very different and had no forewarning of the huge jump in airspeed. I think the Captain did a great job controlling the aircraft. We had compound events and cabin calls all happening at the same time. Perhaps calling the [Relief Pilot] up earlier from his crew break would have alleviated our workload. As the Pilot Monitoring; I could have done more monitoring. Like I stated above; I'm uncertain if this was a true overspeed or part of the electrical anomalies happening with this airplane. The aircraft is still unable to fly.
B777 First Officer reported critical electrical anomalies enroute resulting in unresolved multiple annunciations.