Okay, this is a complex situation with a few potential contributing factors. Let's break it down

Question 1: Can lightning create a surge tripping everything downstream of the device it struck?
Yes, absolutely. Lightning strikes induce powerful transient voltages and currents into electrical systems. These surges can propagate through the system, tripping protective devices (like breakers) regardless of coordination, especially if the surge is strong enough. Here's why: High Surge Magnitude

Lightning surges can easily exceed the instantaneous trip settings of breakers, even those designed for high fault currents.

Propagation

The surge's energy can travel along conductors, affecting breakers downstream.

Voltage Spike

The voltage surge itself can damage breaker control circuits, causing them to trip.

Grounding Issues

Improper grounding or bonding can exacerbate the problem, providing pathways for surges to propagate.

Question 2: Why do the breakers trip simultaneously on motor restart? (Before you adjusted the instantaneous settings)

Here's a breakdown of the likely reasons, assuming the initial lightning strike potentially weakened or damaged the motor or its related components: High Inrush Current & Damaged Motor



High Inrush

A 200 HP motor will have a significant inrush current (locked rotor current) upon startup. You stated the inrush was almost 800 amps, which is significant.

Motor Damage

The lightning strike might have caused minor damage to the motor windings (insulation degradation). This wouldn't necessarily prevent the motor from starting, but it could increase the inrush current slightly due to slight shorting in the windings. It could also lead to increased winding temperatures.

Combined Effect

The high inrush current combined with any potential lightning-related degradation could push the total current over the instantaneous trip settings of all the breakers involved, even the main.

Breaker Coordination Problems (Exacerbated by the Situation)



Ideal Coordination

In a properly coordinated system, the breaker closest to the fault or overload should trip first, limiting the disruption. The upstream breakers should only trip if the downstream breaker fails to clear the fault.

Instantaneous Trip Overlap

The instantaneous trip settings of your breakers were likely too close to each other, or possibly even overlapping. This means that a high current (like a motor inrush current), could trigger all of them almost simultaneously. The fact that the motor was showing 800 amps of inrush proves that it was not high enough to trip the 2500 amp main alone, or the 800 amp feeder, but that it was possible that the downstream breaker tripped first, and then the current was seen by the other breakers who may have been overloaded beyond their instantaneous trip setting, or their thermal trip setting for a short amount of time.

Other Contributing Factors



Voltage Sag

The high inrush current could cause a voltage sag in the entire electrical system. This voltage sag could then affect the operating characteristics of the breakers, potentially making them more sensitive and prone to tripping.

Harmonic Distortion

Motor starting can generate harmonic distortion in the electrical system. This distortion can affect the accuracy of current measurements and potentially contribute to breaker tripping.

Why Simultaneous Tripping?

Even with some degree of coordination, simultaneous tripping can occur because: Speed of Breakers

Modern breakers react very quickly. If the fault current is high enough, even a small difference in tripping times between breakers might not be enough to prevent them all from tripping.

Surge Propagation

Lightning surges can introduce very steep wavefronts (rapidly rising currents). These wavefronts can saturate current transformers (CTs) within the breakers, making it difficult for the breakers to accurately measure the current. This could lead to incorrect tripping.

Common Mode Interference

Lightning surges can introduce common mode interference into the breaker control circuits. This interference can cause the breakers to trip simultaneously, even if the fault current is not high enough to trip them individually.

Regarding Your Actions and Observations



Adjusting Instantaneous Settings

You likely reduced the instantaneous trip settings on the breakers, allowing the motor to start without tripping them on the inrush current. However, you need to be careful about how low you set these settings, as this could compromise the protection of the system against short circuits.

Warm Windings (650A Inrush, 150A Running)

The fact that the motor windings were warm after the second start attempt (and drawing a slightly lower inrush) is a significant concern. This suggests potential damage to the motor windings:

Insulation Weakening

The lightning strike may have weakened the insulation in the motor windings. This is a very common cause of motor failure after lightning storms.

Shorted Turns

Some turns within the motor windings might have shorted together. This would reduce the motor's impedance, increase the current draw, and generate heat.

Recommendations


Motor Inspection

Immediately have the motor thoroughly inspected by a qualified motor repair shop. They should perform:

Insulation Resistance Test (Megger Test)

To check the condition of the winding insulation.

Surge Comparison Test

To detect any turn-to-turn shorts in the windings.*

Visual Inspection

Look for any signs of damage, such as discoloration, burnt insulation, or loose connections.2.

Breaker Coordination Study

Have a qualified electrical engineer perform a full breaker coordination study. This study will determine the optimal settings for all your breakers to ensure proper protection and minimize unnecessary tripping. This should also include a review of the time-current curves of your breakers.3.

Surge Protection

Install surge protection devices (SPDs) at the main service entrance, at the MCC, and possibly even at the motor itself. This will help to protect your equipment from future lightning strikes and other voltage surges.4.

Grounding and Bonding Review

Ensure that your grounding and bonding system is properly installed and maintained. This is critical for mitigating the effects of lightning strikes and other electrical disturbances.5.

Consider a Soft Starter

If the motor inrush current is consistently causing problems, consider using a soft starter or variable frequency drive (VFD) to reduce the inrush current during startup. This will help to protect your electrical system and prolong the life of the motor.6.

Review PLC Logic

Double-check the PLC logic controlling the motor. Make sure there are sufficient time delays between restart attempts to allow the motor to cool down and the voltage to stabilize.7.

Thermographic Scan

After the motor is back in service, periodically perform a thermographic scan to monitor the temperature of the windings and connections. This will help to detect any signs of overheating, which could indicate a problem with the motor or the electrical system.

In summary, the lightning strike was likely the initiating event. The simultaneous tripping was probably due to a combination of a high inrush current, breaker coordination problems, and potential damage to the motor windings. The warm windings are a serious red flag, and you need to have the motor inspected immediately.Safety is paramount. Work on electrical equipment only if you are qualified and trained. If you are unsure about anything, consult a qualified electrician or electrical engineer. Flag for review