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发表于 2014-12-31 11:34:51
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本帖最后由 shanby 于 2014-12-31 11:45 编辑 - N# G Q' \8 {6 e$ C
接线情况:模拟2台150MW,35kV的发电机分别接入2台分裂升压变压器,再由220kV接入大电网。在35kV母线接 ...
, P! j( F* G( Q k8 o0 L5 xshanby 发表于 2014-12-21 21:06 7 @# x# B3 @- s$ Y; ]4 |# P
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, Q& A. v9 O1 [- h 查看如下帮助文档:Assumptions+ ?' M7 H7 d% N ^' N/ M
The electrical system of the Simplified Synchronous Machineblock consists solely of a voltage source behind a synchronous reactanceand resistance. All the other self- and magnetizing inductances ofthe armature, field, and damping windings are neglected. The effectof damper windings is approximated by the damping factor Kd. The threevoltage sources and RL impedance branches are Y-connected (three wiresor four wires). The load might or might not be balanced.Limitations' ~# J$ G+ ^; U. I6 C o
When you use Simplified Synchronous Machine blocks in discretesystems, you might have to use a small parasitic resistive load, connectedat the machine terminals, in order to avoid numerical oscillations.Large sample times require larger loads. The minimum resistive loadis proportional to the sample time. As a rule of thumb, remember thatwith a 25 μs time step on a 60 Hz system, the minimum load isapproximately 2.5% of the machine nominal power. For example, a 200MVA simplified synchronous machine in a power system discretized witha 50 μs sample time requires approximately 5% of resistive loador 10 MW. If the sample time is reduced to 20 μs, a resistive loadof 4 MW should be sufficient.2 i4 c. Y7 @3 M( I* X% y7 V
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得出:
$ }; S6 a N. J. e7 M" `1.简单同步发电机模型采用带电阻和电抗、独立电压源,三相Y连接的电气模型;
4 h0 A! H7 |1 l2.使用边界限制:如果是采用离散系统仿真,则需要在发电机端子连接寄生小电阻,其阻值或功率与离散系统的采样时间成比例(举例有计算实例)% [$ E, G) u; @
4 K1 ]/ V# x: e试错结论:
$ [) w& E: ?, R8 {# A1.错误提示说简单同步发电机是电流源,需要并联高值电阻。这与帮助文档电压源的说法不一致(尽管电压源和电流源和也互相变换)
" r0 {; X3 _* X7 i, \- L9 P; {' Q( R2 S& U2.将powergui模块参数设置为continous,仿真报错与设置为discrete的报错信息一样。# R$ V5 F+ t6 L0 c) p
3.将powergui模块参数设置为discrete, 按错误提示边栏电阻,则仿真不报错(虽然结果不是预期)。) m" F1 N7 ^/ c3 u8 j; s
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ShortCurrentFor300MW2.rar
(9.71 KB, 下载次数: 1)
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电压波形
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疑问:
( |# I" p' E9 J: C1.如何解释模型搭建、报错和试错结论?3 a% e M8 u C1 z1 @$ C W
2.Simulink仿真的逻辑?6 P* i: Y5 @# j8 w( @8 m
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