是什么导致电能质量差?

There are a number of causes for poor power quality, including, 高压, 低压, 没有电压, 电噪音, impulses, 或者是这些的组合. In addition, research shows that many power quality problems are due to improper ground connections.

常用术语:

高压  |  低压  |  没有电压  |  电噪音  |  Impulses

高压 is any voltage exceeding 110% of what is known as nominal voltage: 120, 208, 240, 277, 480 -取决于应用程序.

Momentary occurrences of high voltage are known as voltage swells and could occur as a result of a sudden decrease in electrical load. 中性点连接松动, or faulty wiring on a 120-volt circuit can allow a voltage swell to damage electronic equipment. Equipment operating at 240-volts such as air conditioners, water heaters, ranges, ovens, etc., are not typically affected by voltage swells.

低压 是否有电压低于正常电压的90%.

Momentary occurrences of low voltage are known as voltage sags and can occur as a result of an overloaded electrical system, 要么在公用事业方面, or on the internal wiring of the customer's home or business. Electrical faults can cause sags on adjacent circuits or feeders.

The start-up of large motorized devices such as A/C systems or pumps can pull voltage down to where electronic device operation is affected. Many energy efficient heat pumps require large amounts of electrical current to start unless a "soft-start" kit has been installed.

没有电压 is a complete loss of power that can last from milliseconds to several hours. Momentary interruptions usually last less than one minute.

电噪音 or Electro-magnetic disturbances on a wiring system can be caused by improper wiring and grounding, 内部或外部连接不良, 不适当的屏蔽, 大型汽车公司, or the use of arc-type equipment such as welders. Symptoms of these problems for sensitive electronic equipment include audible or visual distortion, 不稳定的数据问题或系统错误消息.

Impulses, 称为瞬态浪涌, 或者电压尖峰, are the most common cause of damage to electronic devices and other sensitive equipment. These impulses can be hundreds of volts above normal, but last only millionths of a second. Transient surges are what surge protection devices are designed to arrest or minimize.

If you believe that you're having a power quality problem, 第一步是诊断你的问题.

例如, if your power goes off for 1-2 seconds at random intervals, 或者在雷雨天气, 这将被归类为短暂中断, i.e. 闪烁时钟综合症. This is usually caused by utility circuit breakers opening to clear a temporary fault or short circuit in the power lines. 故障可能是由雷击引起的, 大风, animal or automobile contact with power equipment. 如果是暂时性故障, the automatic line circuit breakers will re-energize the power line to restore normal service. These line circuit breakers help prevent damage to power lines and equipment which could cause long term outages.

防止暂时中断的保障措施, 特别是如果电脑可能受到影响, is the installation of an uninterruptible power supply (UPS), 或备用电源(SPS)单元.

SPS units are the least expensive and feature an electronic switch that transfers the load to a battery upon the loss of regular power. The switch occurs faster than a computer can react and provides power from 8 to 15 minutes, allowing ample time to close down critical programs. 这些装置的价格低至80美元, and would be a good investment towards the protection of your computer data.

However, there may be more to the problem than just a power loss. Whatever caused the momentary outage (such as lightning) could also end up causing damage to the customer's equipment. "The power went off, and when it came back on, my computer was damaged!" The real problem was the incident that caused the line circuit breaker to momentarily trip and not the power going off and on.

防浪涌保护

Warning – a nearby lightning strike could induce a 高压 surge on your building's interior wiring, 绕过主要服务的主要单位. 在这种情况下, the individual plug-in units serve as the primary protector, 因此需要一个高质量的插件单元. These units also come with multi-port protection, so that the phone line or video cables going to the sensitive electronic devices could be protected. Phone lines and video cables transmit a large percentage of the surges that can cause sensitive electronic equipment damage.