Question

State the necessity of synchroscope and with neat sketch explain its working.

Answer 1

### Necessity of a Synchroscope

A synchroscope is an important device used to measure and indicate the synchronization of the speed, frequency, and phase of an incoming alternator (generator) with the existing grid or system. This ensures that both systems are operating at the same frequency and phase before they are connected (synchronized). The necessity of a synchroscope includes:

1. Prevent Damage to Equipment: If the alternators are not synchronized correctly, it can cause mechanical stress on the generators, damage to turbines, and lead to faults like short circuits.
   

  

1. Prevent Power Disturbances: Improper synchronization could result in power surges, voltage dips, and phase imbalances, affecting the quality of power supplied and possibly damaging sensitive equipment.
   

  

1. Efficiency: Synchronization ensures smooth and efficient operation of generators in parallel. It allows the generators to share the load properly without overloading any unit.
   

Working of a Synchroscope

A synchroscope shows the difference in phase between the incoming generator and the grid. It uses a needle or digital display that moves as the incoming generator's speed and phase are compared with the grid.

Working Principle:

The synchroscope works by comparing the voltage of the incoming generator with the grid’s voltage. The device uses a mechanical or electronic system to detect when the phase angle of the incoming generator matches that of the grid. The closer the incoming generator’s frequency and phase are to the grid, the more aligned the synchroscope needle becomes, indicating that synchronization is ready.

Steps for Synchronization using a Synchroscope:

1. Monitor the Needle Movement: The synchroscope has a needle that moves according to the phase difference. The needle moves to a specific point when the generator and grid are in phase.
   

1. Slowly Adjust Speed: The operator adjusts the speed of the incoming generator to match the grid frequency. This is done by controlling the excitation or governor system of the generator.
   

1. Align the Needle: When the incoming generator’s frequency and phase are matched with the grid, the needle on the synchroscope moves to the center (usually 12 o’clock position).
   

1. Close the Breaker: Once the needle is centered, the circuit breaker is closed, and the generator is synchronized and connected to the grid.
   

Neat Sketch of a Synchroscope

Here's a simple sketch that explains the working of a synchroscope:

---

`
                     --------------------------
                    |                          |
                    |   Synchroscope Meter     |
                    |                          |
                    |    _______      _______  |
                    |   |       |    |       | |
                    |   |       |    |       | |
                    |   |       |    |       | |
                    |   |       |    |       | |
                    |    -------      -------  |
                    |                          |
                    --------------------------
                        |              |
                        |              |
                Incoming Generator      Grid Power
                    |                       |
                    |      Phase Difference |
                      ---/-------------------
                             Synchronizing
`

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In the above sketch, the synchroscope meter has a rotating needle that indicates how close the generator's phase is to the grid's phase. When the needle is at the top (12 o'clock position), the generator is in sync with the grid, and the circuit breaker can be closed to connect them.