电力系统基础知识很实用！！！

V123456789 发表于 2007-12-13 10:05:24

为什么下载不了呢？

wuyangxun001 发表于 2007-12-13 17:21:18

好东西啊,谢谢分享!

liuyouyuan23 发表于 2007-12-14 12:06:03

是个好东西
谢谢了
顶起！！！！！！！！！！！

DONGBEI 发表于 2007-12-23 22:20:53

Icrease ransmission line loadability arter 2003 Blackout

I have Modified the settings of protection in North American Ccompany associated with NAERC (North American Electric Reliability Council) recommendation 8A
Major tasks performed:
In the aftermath of the august 14, 2003 Blackout, IEEE and NERC study groups have produced a number of documents dealing with transmission line loadability. The documents provide guidelines with respect to the means by which the loadability of transmission line can be increased, if the loading is limited by characteristic of the distance protection on the line.
I would like to discuss about protetion and control problems in engineering with you.

DONGBEI 发表于 2007-12-23 22:29:31

Several methods to increase loadability

1. Enable the load encroachment function such as for SEL -321 Relay
Enabling load encroachment features on existing programmable IED logic in SEL-321 relays will increase line loadability. The load encroachment feature of relay could be set 150 % and 0.85 per unit voltage at a 30 degree power factor angle.
2. Change the impedance relay characteristic from a circle to s lens for L-PRO 2200E, D60, and MICROMHO relays
Electronic Relays was a mho distance type relay. That relay’s characteristic could be modified from a mho to lens. The characteristic angle IN L-PRO 2200E could be increased larger than 90 degrees while the Comp Limit in D60 and MICROMHO relays could be decreased less than 90 degrees.
3. Increase the angle of maximum torque (reach) for KD relays
In KD case the factory MTA is 75 degree, a common angle for electromechanical relays. To increase line loading, MTA angle can be adjusted on some relays as far as 90 degrees. Such adjustments can increase line loadability as measured along the 30 degree load apparent impedance line.
KD relay is a kind of electromechanical relays. It needs to increase the angle of Maximum Torque (MTA) to keep the Zload 30 point out of the 3Φ zone 2 impedance circle. This is accomplished with the removal of three compensation resistors which will change the MTA of the impedance circles to 90 degrees.
Modify KD settings as follow:
Firstly, from Zload 30 point calculates the Required MTA.
The Required MTA = Arc COS (Zload30 Reach /Zone 2 Reach) +30
A. If the Required MTA > 90 degrees, then need to shift MTA to 90 degrees and reduce the impedance reach at the same time.
If the Required MTA < 90 degrees, then need to shift MTA to 90 degrees and not need to reduce the impedance reach.

Gavin1983 发表于 2007-12-25 22:42:45