过电压的定义和产生
电力系统中存在着大量的“储能元件”,这就是储静电能量的电容和储磁能的电感。这些元件组成了各种不同的振荡回路,在正常运行时,这些振荡回路被负载所阻尼或分路,一般不会产生严重的振荡。但在发生故障时,系统接线方式和参数发生改变,就有可能发生谐振。
谐振过电压又可分为线性谐振、参数谐振和铁磁谐振
There is a large number of "energy storage elements" in the power
system, which is the capacitance of electrostatic energy and the
inductance of the storage magnetic energy. These components make up a
variety of oscillating loops that are damped or separated by the load
during normal operation and generally do not produce severe
oscillations. However, in the event of failure, the system wiring mode
and parameters change, and the resonance can occur. Can be divided into
the linear harmonic resonance overvoltage, parameter resonance and
ferro-resonance
线性谐振分析
Linear resonance analysis
自振频率等于或接近电源频率时形成的谐振现象。即ω=ω。=1/√LC。
实际电力系统中,往往可以在设计或运行时避开这种谐振,因此完全满足线性谐振的机会是极少的。但是,即使在接近谐振条件下,往往也会产生很高的过电压,所以要加装TBP过电压保护器。
A resonant phenomenon formed when the frequency of vibration is equal to
or near the power frequency. The omega = omega. LC = 1 /). In the
actual power system, it is often possible to avoid such resonance in
design or operation, so the chance of fully satisfying the linear
resonance is very rare. However, even close to the resonant condition,
it often produces high overvoltage, so it is necessary to install TBP
overvoltage protector.
线性谐振过电压幅值受到回路中损耗(电阻)的限制;同时,在有些情况下,由于谐振时电流的急剧增加,回路中的铁磁元件趋向饱和,使系统自动偏离谐振
状态而限制其过电压幅值。
The linear resonant overvoltage amplitude is limited by the loss
(resistance) in the loop. At the same time, in some cases, due to the
sharp increase of current in resonance, the ferromagnetic element in the
loop tends to saturate, so that the system automatically deviates from
the resonance state and limits its overvoltage amplitude.
参数谐振分析
Parametric resonance analysis
系统中某些电感元件的电感参数在某种情况下会发生周期性的变化。在某种参数搭配下,就有可能产生谐振现象。
参数谐振所需能量来源于改变参数的原动机。当电感参数变化时所引入的能量足以补偿回路中的损耗,谐振不断发展。对应于一定的回路电阻,有一定的自激范围。谐振发生后,理论上振幅趋向无穷大,而不像线性谐振那样受到回路电阻的限制。但实际上电感的饱和会使回路自动偏离谐振条件,加装了TBP过电压保护器能使过电压得以限制。
The inductance parameters of certain inductance elements in the system
will change periodically in some cases. With some parameter collocation,
it is possible to generate resonance. The energy required for
parametric resonance is derived from the original motivation of changing
parameters. When the inductance parameter changes, the energy
introduced is sufficient to compensate the loss in the loop, and the
resonance develops continuously. Corresponding to a certain circuit
resistance, there is a certain range of self excitation. After the
resonance occurs, the theoretical amplitude tends to infinity rather
than the resistance of the loop like the linear resonance. However, the
saturation of the inductance will automatically deviate the resonant
condition and the TBP overvoltage protector can be applied to limit the
overvoltage.
当发电机带有电容性负载,如一段空载线路,在某种参数搭配下,就有可能产生参数谐振现象。有时将这种现象称作发电机的自励磁或自激。发电机投入电网运行前,设计部门要进行自激的校核,一般正常情况下,参数谐振是不会发生的。
When a generator has a capacitive load, such as an empty line, it is
possible to generate a parametric resonance phenomenon with some
parameter collocation. This phenomenon is sometimes referred to as the
self-excitation or self-excitation of a generator. Before the generator
is put into the grid, the design department should have a self-excited
check. Normally, the parameter resonance will not happen.