电工如何知道线路断开的地方？

29

我停电了，想到了附近的电线杆。考虑到其中的许多英里，电工如何知道哪条电源线断开了？例如，如果有一辆汽车撞到电线杆上并使电源线下降，那么电工（或电力公司）如何知道中断点在哪里？

mains

— Netrox
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5

我没有足够的细节来回答，但实际上，电网不仅仅是一堆交流输电线路和变压器。在网格上的许多位置（例如在某些关闭点，变压器，仪表等处），都有智能设备可以使用各种协议进行通信，并且既可以指示状态，又可以在远程控制下采取某些措施（例如打开/关闭）一个中断器）

— –ζ

30

投诉结束的地方电源中断。

— 伊格纳西奥·巴斯克斯

2

一种可能性是tdr

— PlasmaHH 2016年

1

在许多地区，至少在佛罗里达州，所有变电站都有一个交叉连接的光纤电缆网格，该电缆网格在两个方向上都经过系统状态。他们去的是传递任何“故障”信息反馈给中央控制中心，即使自动响应是建立在“路由器”变电站

— Sparky256

1

如果发生车祸，警察会立即通知电力公司，前提是他们会立即得到通知。

— 戴夫·特威德

52

客户服务电源线通常分为几块或几圈，因此对部分电网的损坏不会使巨大的地理区域失效。变电站可以通过一条大型区域电力线为附近的几个单独的客户电网供电。

每个客户电网在变电站都有自己的断路器，通常配备自动重合闸。在电源故障期间，您可能会注意到电源关闭，重新打开，关闭，重新打开，然后第三次关闭并保持关闭状态。这是由于自动重合闸导致的，它会立即恢复电源。一些线路故障（例如，倒下的死树树枝）是短暂的，并且在树枝滑过线路后可以立即恢复电源。

如果无法清除故障，则通常由重合闸或变电站立即将故障线段报告给区域电网控制中心。通常完全不需要在暴风雨期间停电，因为控制中心会立即知道线路段何时断电。

例如，在YouTube上自动重合闸：

智能电网-自我修复-NOJA Power https://www.youtube.com/watch?v=rVTIwr1Rk2c

无法立即查明无法自动恢复的线段上的故障位置。这些故障通常是由巡边员进入多功能卡车并在附近行驶并检查线路段的每个部分来确定的。他们有详细的地图来指导他们。可以分配多辆卡车检查下段。如果您在停电期间看到一辆电动卡车在街上缓慢行驶，那是因为他们正在目视检查线路。

晚上停电时，多功能卡车配备大功率照明设备。多功能卡车将沿着道路缓慢行驶，一个人对准聚光灯，另一个人看着照明的线路和设备以检查是否损坏。

这是无法自动关闭的断电可能需要几个小时才能恢复的部分原因，因为巡线员需要四处走动并检查所有线路以检查是否有断线，绝缘子损坏，重压冰块的情况线或接触线的对象。

这也是为什么将客户的本地电源线细分为小区域的原因，因为客户线段越大，在停电期间定位故障所需的时间就越多。在恶劣的天气条件下（例如暴风雪或冻雨），寻找线路问题的时间甚至更长。

例如，在YouTube上：

恢复功率的方式 -Puget声能https://www.youtube.com/watch?v=gLikTRjrmnc

一旦发现电源线故障，巡线员将采取额外的安全措施将电源线接地和/或短路，这样，如果在完成其工作之前恢复电源，安全地线将立即重新跳闸。线路断路器，并防止对线路员造成伤害。

安全接地还可以保护巡线员免受家庭电源系统的干扰，因为家庭电源系统的接线可能会错误地将电源回馈至无效线路。小型家用发电机能够回馈到下行电源线，并以其12,000伏（或更高）的工作电压为其供电。安全接地和向下的电源线短路可确保这些错误连接的家庭发电系统将导致保险丝烧断或家庭发电机烧坏，而不是死线。

例如，在YouTube上：

防护接地 https://www.youtube.com/watch?v=T0vZDl2kFI8

对于馈送给某个区域的非常大的传输线（两极比本地电网高得多），这些传输线通常是越野的，可能不在道路附近。可以通过地面车辆进入这些线路进行检查和维修，但是在冬天或下雨或地面柔软且泥泞时，很难进入。

取而代之的是，这些超大型输电线路的检查和维修工作通常是由直升机完成的，由于直升机没有与地面接触，他们可以接近带电的电源线，与之接触并在线路上进行作业仍然充满电时进行维护或修理。

例如，在YouTube上：

通电765,000伏线路上的直升机维护 https://www.youtube.com/watch?v=x94BH9TUiHM

50万伏电力线的绝缘子“热洗”！ https://www.youtube.com/watch?v=lcjhjna9jZE

— 戴尔·马哈尔科（Dale Mahalko）
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1

那么，如果一条大型传输线被拔出怎么办？我知道他们让树木远离树木，因此起初不太可能发生，但出于好奇

— Random832

@ Random832：然后您遇到了重大事件，例如en.wikipedia.org/wiki/Northeast_blackout_of_2003

— mharr

1

但是，当然，对于我们其他人来说，确切的问题出在哪里，仍然取决于那些在卡车上四处行驶的家伙，寻找导致问题的下降线/跨线分支/松鼠。（别笑了-我们曾经有一次松鼠造成停电，他把脚放到一个绝缘子/电线上，而前脚放到另一个绝缘子/电线上，然后放... ZZZZZ-OTTTT！（黑暗）。来了，拿出了可伸展的电线杆，将绝缘体上的残留物敲了敲，回到变电站，然后... LIGHT！:-)

— Bob Jarvis-恢复莫妮卡

1

@mharr There were multiple factors that led to that blackout, notably lack of visibility to a large part of the system. Transmission lines going down don't usually result in widespread blackouts, especially these days.

— Carl Kevinson

A tornado caused a 3.5 day blackout for this area a few years ago. This whole county (and more) normally gets power from just one power plant. The tornado came close to that power plant, and took down all the high-voltage power lines to this county. It took 3.5 days to restore just one of the several paths that would allow the power to reach this county again, and longer to restore power to some areas with more direct damage from that day's tornadoes.

— user6030

16

By the way, Dale's answer is quite good, and I mean only to append to it.

他们有一个通过电力线发信号的系统。它不是特别高的比特率，但是可以完成工作。许多智能电表可以通过这种方式接收或发送。如果您打电话给他们并要求他们，通常他们可以远程关闭您的电源。他们还可以通过这种方式获取电表读数。当然，他们在顶杆上还有其他显示器，有些带有蜂窝，无线电或有线连接，可以为它们下游的电台中继。

如果极杆或变电站断路器或重合闸跳闸，通常可以打电话回去。

不用说，询问网络并获取地图并不难。当然，从PC板布局可以知道，原理图上较短的一段可能会很长，甚至分支在PCB上。因此，这可能会显示一段长达数英里的路段，并且必须沿着铁轨，后院或玉米田进行人工检查-电力线并不总是沿着道路行驶。

过去他们是如何做到的？客户打进来。他们得到了一个手电筒，从电话簿的紧急联系页面上读取电话号码，拿起电话，听到拨号音，然后致电电力公司并进行了举报。

How did they get a dial tone with no AC power? Wireless phones which need a powered base station weren't common. U-verse didn't exist. The phone was powered through the phone line itself, from massive submarine sized batteries in the central office, backed with burly Caterpillar generators. I've been through 5-7 day outages where phone reliability was never in question.

— Harper - Reinstate Monica
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So how'd the phone company deal with their outages?

— Random832

2

@Random832 Diesel generators.

— Michael Hampton

@MichaelHampton I meant, if a phone line was cut, how was the outage reported.

— Random832

1

@Random832 From a neighbor's house, or from a pay phone.

— Michael Hampton

@Random832, it looks like Graham's answer pertains to your phone line question. @ MichaelHampton, that's great...

— JPhi1618

13

Time-domain reflectometry is your friend here. Electrical conductance isn't as simple as it looks. If you put a pulse on the broken line, you'll get a reflection of that pulse coming back from wherever the line is broken. Measure the time between first and reflected pulses, divide by the propagation speed in that cable, and you have your distance.

— Graham
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Does this also work for other line faults, such as short circuits?

— Mark

@Mark: it can, when the circumstances are right

— PlasmaHH

@Mark From the point of view of a power line, what you think of as a "short circuit" is just a change in impedance.

— Graham

2

Most smart meters transmit in the 902-928 mhz band at low power and transmit to the next house then that meter then transmits to the next house in the chain until it encounters a data receiver that then uploads it to the power company via cell phone link. Each power meter has it own ID# and if no data is received the power company exactly where the outage is complete with street addresses of the customer.

— Old_Fossil
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You're assuming smart meters have been installed; here in Queensland (Australia), they basically don't exist (there was a small trial recently, and the other day I saw the meter reader read the neighbour's meter). Currently, I believe Victoria (think Melbourne) is the only area in AU with a significant roll-out of smart meters. In Brisbane, many homes still have the old analog meters with their multi-dial 'displays' and spinning wheel.

— Calrion

I can only answer for Canada. We had the old analog ones that you could mess with about a year and a half ago.

— Old_Fossil

And I know they have the powerline based system too, because I was able to get a remote power drop shut off remotely - it was too far from other boxes for what you describe to work.

— Harper - Reinstate Monica

@Harper: Are you in a rural or urban area? This info I quoted was from power company sources. In this instance it was Hydro Quebec and Ontario 1.

— Old_Fossil

In that case, quite rural. It's clear the various power companies are using a mishmash of technologies.

— Harper - Reinstate Monica

0

Electrical Grid control rooms have the ability to pinpoint to within 3 meters where power goes out on modern electrical grids. It's not just electricity that flows through the lines. It's status, and control signals as well. It's similar to being a large computer network. We can control the power to certain sub-stations, de-energize a transformer (thus turning off power to a neighborhood, house, apartment, etc) and with the new Smart Meters here in BC, we can turn on, and off the power right at your house which is super handy in emergencies. Say fire, or flood. The 1st responders won't go into a place that is still energized, and risk themselves getting hurt or killed, so when that call comes in, we can just turn the power off with a couple clicks of a mouse.

— Rhinofart
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0

Every city has its circuit breakers. every grid has circuit breakers. Every sight has its circuit breakers. All these breakers are basically PLC. These all PLC are connected to NMS (Network manangement sytem) These NMS works on SNMP model. when a site goes down. Circuit breaker is tripped and it will show alarm on NMS. So electricians know the exact place of network failure. I think so understand how these circuit breakers work.

— Danish Ali Chaudhary
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