# Tagged Questions

563 views

### 3-phase power calculation when phase to phase voltages are different

I have a 3-phase power supply rated at 230VAC per phase. However, the phase to phase voltages are not equal. Suppose $V_{RY}$, $V_{YB}$ and $V_{BR}$ be the three phase-to-phase voltages between ...
517 views

### Why are the power transmission/distribution systems AC and not DC?

Is there a good reason why we are not in the process of completely converting our electrical transmission system to DC? The main reason for using AC on the grid (no offense Tesla, I love you man) was ...
193 views

### What causes sub-second mains voltage outages?

Many times I observed a following electrical event: mains voltage will suddenly drop and then immediately restore. This causes lights to blink and computers to restart. I can't imaging what could ...
843 views

### What electrical anomaly can cause RCBOs to trip in apartments in several buildings at the same time?

Once I had a weird electrical event in an apartment building I live in. Suddenly the Residual Current Circuit Breaker with Overload protection (I'm sure it's exactly this kind of device) in the main ...
2k views

### What causes unequal phase-to-neutral voltages in three-phase distribution systems?

A four-wires cable runs into an apartment building to supply it with three-phase 380/220V alternating current. Each apartment is connected to one phase, different apartments are connected to different ...
538 views

### How do utility companies treat voltage deviations in distribution networks?

I live in a region where nominal mains voltage is 220 volts and state standards permit deviations within 5 percent continuously and within 10 percent for short periods. So if I measure the voltage in ...
5k views

### What causes overvoltage in power grid?

In the region where I live there's a state standard that says that mains voltage deviation can be within 5 percent continuously and within 10 percent for short periods of time, so if the mains voltage ...