加装零序电压互感器
加装零序电压互感器的消谐型电压互感器由三相主电压互感器TV1和串接在中性点的零序电压互感器TV0二部分组成,采用零序电压互感器消除谐振,见图2。该消谐装置要求TV1的开口三角绕组闭合,零序电压U0从TV0的二次侧取得。当单相接地时,TV每相励磁感抗为Xm=XTV1
3XTV0(XTV1 为TV1的漏抗;XTV0为 TV0励磁感抗)。
The harmonic elimination voltage transformer with zero sequence voltage
transformer is composed of three-phase main voltage transformer TV1 and
zero sequence voltage transformer tv0 connected in series at the neutral
point. Zero sequence voltage transformer is used to eliminate
resonance, as shown in Figure 2. The device requires the open delta
winding of TV1 to be closed, and the zero sequence voltage U0 is
obtained from the secondary side of tv0. When the single-phase is
grounded, the excitation reactance of each phase of TV is XM = xtv1
3xtv0 (xtv1 is the leakage reactance of TV1; xtv0 is the excitation
reactance of tv0).
由于XTV1很小,可略,故Xm≈3XTV0,即零序电压绝大部分降落在TV0上,一般的外激发不能使TV1进入饱和区,从而使谐振难以产生。此外,TV0高压绕组的直流电阻约为10kΩ,对谐振有强烈的阻尼作用,对涌流有限制作用。此种消谐型TV的消谐作用也仅对自身有效,热容量也有限。
Because xtv1 is very small, it can be omitted, so XM ≈ 3xtv0, that is,
most of the zero sequence voltage falls on tv0, and the general external
excitation can not make TV1 enter the saturation region, so that
resonance is difficult to produce. In addition, the DC resistance of tv0
high-voltage winding is about 10K Ω, which has a strong damping effect
on resonance and a limiting effect on inrush current. This kind of TV is
only effective for itself, and its heat capacity is limite