内容来源：https://www.engadget.com/2261632/why-important-unplug-pc-power-outage/

内容总结：

停电时拔掉电脑电源，可能是保护电脑最有效的办法。电源中断通常毫无预兆，多数人第一反应是找手电筒，而不会想到电脑。但如果恢复供电时电脑仍插在墙上，它可能面临损坏风险。很多人以为电脑因停电关机就安全了，其实不然。即使电脑已经关机，它仍与家中电路相连，而这种连接正是损坏发生的途径。主板、内存和固态硬盘等部件由精密电路构成，对异常电压尖峰非常敏感。

当电力突然中断，无论是因为电网过载、设备故障还是跳闸，电力系统并不会简单“安静下来”。在停电前后瞬间，电压可能剧烈波动，而恢复供电时产生的浪涌往往比停电本身更具破坏性。美国家庭标准电路为120伏，即使只是适度超出这一水平的电压尖峰，也足以永久损坏敏感的电脑部件。

关机并不够

即使你在停电前已关闭电脑，也未必安全。恢复供电后，电流仍可能通过电源线进入内部组件，即使机器处于关闭状态。电涌是最常见的原因，通常由雷击或附近电力线路损坏引发。即使闪电没有直接击中房屋，也可能通过当地变压器将浪涌送入家中线路。电网恢复供电时，往往还会带来额外电压尖峰，因此危险并不会随着灯光亮起而结束。此外，如果电脑在断电时正在运行，突然断电本身也会带来问题。正在保存或更新的文件可能损坏，若发生在系统更新期间，可能导致系统无法使用。如果电脑使用机械硬盘，突然关机还可能损伤其机械磁头。

如何保护电脑

如果知道极端天气即将到来，应关闭系统并拔掉电源。如果已经停电，也仍值得拔掉电脑。路由器也应一并拔掉，它是雷暴中最容易被烧坏的设备之一，而且本来也应定期重启。电视等其他昂贵电子产品也应拔掉。台式机可关闭电源供应器，以阻止电流进入系统，但雷击等极端情况仍可能造成损坏。优质电涌保护器是更好的选择，可吸收电压尖峰。不间断电源更佳，它结合电涌保护与电池备份，可在短时停电时防止关机，给你时间保存工作并正常关机。若需更全面保护，可请持证电工在配电箱安装电涌保护装置。恢复供电后也不要立刻插回所有设备，应等待几分钟，确认不会再次停电。重新连接时，先插电涌保护器，再插电脑和外设。

停电时拔掉电脑只需几秒钟，却是保护投资最有效的方法之一。配合电涌保护器或不间断电源，这一简单习惯将降低硬件损坏或数据丢失的风险。考虑到可能付出的代价，这点努力微不足道。

中文翻译：

为什么停电时拔掉电脑插头很重要
停电时拔掉电脑插头，可能正是保住电脑的关键。
停电通常不会提前通知。一旦停电，大多数人只顾着找手电筒，而不会想到自己的电子产品。但如果恢复供电时你的电脑还插在墙上，它可能就危险了。
很多人以为，电脑（不情愿地）关机就足以在停电期间保它平安，但事实并非如此。即使电脑已经关机，它仍然与家里的电路相连，而这种连接正是损坏发生的途径。电脑尤其脆弱，因为主板、内存和固态硬盘等部件的精密电路对突如其来的电压尖峰非常敏感。
风险之大值得了解。当电力意外中断时，无论是电网过载、设备故障还是断路器跳闸，电力系统并不会就此安静下来。在停电前后那段时间，电压可能剧烈波动，而恢复供电时涌来的浪涌，往往比停电本身更具破坏性。美国标准家用电路为120伏；即使是高于该水平的适度尖峰，也足以永久损坏敏感的电脑部件。
了解如何保护你的设备，可以让你免于高昂的维修费用、数据丢失以及寻找替换零件的头疼。
关机还不够
即使你在停电前已经关掉了电脑，也不一定就安全。恢复供电后，电流仍可能通过电源线进入内部组件，哪怕机器处于关机状态。
电涌是造成这种情况最常见的原因；当电流突然激增时就会发生电涌，通常由雷击或附近电线受损引发。即使雷击没有直接击中你家，也可能通过附近的变压器把浪涌送入你家电路。停电后电网恢复时，往往还会再来一次电压尖峰，所以灯亮了并不意味着危险结束。
此外，如果停电时你的电脑正在运行，突然断电本身也会带来问题。正在保存或更新的文件可能会损坏，如果恰好发生在系统更新期间，甚至可能让你的系统无法使用。如果你的电脑用的是机械硬盘，突然关机还可能损伤其机械磁头。
停电时如何保护你的电脑
为了确保电脑在暴风雨中不受损害，当你知道极端天气即将来临时，先关机再拔掉墙上插头。如果已经停电了，仍然值得把机器拔掉。顺便把路由器也拔了，因为它是雷暴中最容易被烧坏的设备之一。反正你本来就该定期重启路由器，拔掉也无妨。其他贵重电子产品，比如电视，也一并拔掉以求安全。
对于台式电脑，关闭电源供应器也有帮助，因为这样可以阻止电流进入系统。然而，像雷击这样的极端事件仍可能造成损坏。电涌保护器是更好的选择。优质的电涌保护器充当第一道防线，在电压尖峰到达你的设备之前将其吸收。
投资一台UPS更好。不间断电源将电涌保护与电池备份结合在一起。虽然它的目的不是让你的设备运行数小时，但它可以防止短时停电导致关机，并给你一个窗口保存工作、从容关机，而不是瞬间断电。如果需要更全面的保护，可以考虑请有执照的电工在配电箱处直接安装电涌保护装置，为家中每一个插座提供防护。
另外，恢复供电后，不要立刻急着把所有东西插回去。等几分钟，确认不会再停电。重新连接时，先插电涌保护器，再插电脑和任何外设。
停电时拔掉电脑插头只需几秒钟，但这是保护你的投资最有效的方法之一。再配合电涌保护器或UPS，这个简单的习惯将降低硬件损坏或数据丢失的可能性。考虑到可能付出的代价，这点努力实在微不足道。

英文来源：

Why it's important to unplug your PC during a power outage
Unplugging your PC during a blackout might be exactly what saves it.
Power outages don't usually come with a schedule. And when one hits, most people focus on finding the nearest flashlight rather than thinking about their electronics. But if your PC is still plugged into the wall when the lights come back, it could be in danger.
Many assume that a PC (unwillingly) shutting down is enough to keep it safe during an outage, but it isn't. Even a powered-off computer remains connected to your home's electrical wiring, and that connection is exactly how damage occurs. PCs are particularly vulnerable, since components like the motherboard, RAM and SSD are built with delicate circuits that are sensitive to unexpected voltage spikes.
The scale of risk is worth understanding. When power cuts unexpectedly, whether due to grid overload, equipment failure or a tripped breaker, the electrical system doesn't simply go quiet. Voltage can fluctuate sharply in the moments before and after an outage, and the surge that arrives when power is restored is often more damaging than the outage itself. Standard household circuits in the US operate at 120 volts; even moderate spikes above those levels are enough to permanently damage sensitive computer components.
Understanding how to protect your setup can save you from costly repairs, loss of data and the headache of tracking down replacement parts.
Turning off your PC isn't enough
Even if you turned off your PC before the power outage, it's not necessarily safe. Electricity can still travel through the cord and reach internal components once power comes back on, even while the machine is dark.
Power surges are the most common cause of this; they happen when there's a sudden jump in electrical current, often triggered by lightning or damage to nearby power lines. Even a strike that doesn't directly hit your house can send a surge through your local transformer and into your home's wiring. When the grid comes back online after an outage, it often delivers an additional spike, so the danger doesn't end when the lights come back on.
On top of that, if your PC is running when the power cuts off, that sudden loss of power can cause its own problems. Any files being saved or updated may be corrupted, which could render your system unusable if it happens during OS updates. If your computer has HDDs, sudden shutdowns can also harm their mechanical heads.
How to protect your PC during a power outage
To ensure your PC doesn't suffer any damage during a storm, shut down your system and unplug it from the wall when you know extreme weather is coming. If the power is already out, it's still worth unplugging the machine. Do the same for the router while you're at it, as that's one of the most frequently fried devices in an electrical storm. You should be restarting your router regularly anyway, so unplugging it won't hurt. Keep other expensive electronics like your TV safe by unplugging them too.
On a desktop PC, shutting off the PSU can help since that prevents current from entering the system. However, an extreme event like a lightning strike could still cause damage. A surge protector is a much better idea. A quality surge protector acts as a first line of defense, absorbing voltage spikes before they reach your equipment.
Investing in a UPS is even better. An uninterruptible power supply combines surge protection with a battery backup. While it's not meant to keep your devices running for hours, it will prevent shutdowns during short outages and give you a window to save your work and shut down gracefully instead of losing power instantly. For broader coverage, consider having a licensed electrician install surge protection directly into your electrical panel, shielding every outlet in the house.
Also, when the power returns, don't immediately jump at the chance to plug everything back in. Wait a few minutes to ensure it won't go back out again. When you reconnect, plug your surge protector in first, then your PC and any peripherals.
Unplugging your PC during a power outage takes only a few seconds, but it's one of the most effective ways to protect your investment. Paired with a surge protector or UPS, the simple habit will reduce the chance of hardware damage or data loss. Given what's at stake, it's a small effort to make.