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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 6 x) Q" U' F+ R6 n+ a; L4 W* b
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 ...
! j4 [$ g7 r) L0 ^; c) }# @% zshanby 发表于 2014-12-21 21:06 * H0 M! C7 q- Z. M }
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查看如下帮助文档:Assumptions7 n6 S8 u4 o8 k
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( t7 z( P/ ~% \: r. G
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. @. f( {/ V1 J' ^& N
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得出:
+ F5 K: F+ n) J0 |. [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;
. Y: a3 |/ K5 m9 S$ l8 k2.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)) u% e1 Q8 z% @# N! }
& I. Z" @; n: M试错结论:
4 t/ S! S/ Y @: r1.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)# }: b" r: `" l+ ]
2.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。
* G* h/ t7 U7 G. T3.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)。: K% g1 r1 B. p5 \9 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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0 c; d* b% s" V+ K/ y s) D; j疑问:6 l( {8 o8 ]) F6 N" b7 U6 Z
1.如何解释模型搭建、报错和试错结论?/ V, f- {2 K1 U" U
2.Simulink仿真的逻辑?
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