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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 1 l# n3 S1 t7 `
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 ...! x1 k! r) X& r) }
shanby 发表于 2014-12-21 21:06
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9 L% {9 o! D; l: v4 D 查看如下帮助文档:Assumptions% @' z9 @2 U; h! y. B8 e9 R. U) n" U
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
, X* `# Q9 [' M: e8 b) ^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 c4 n/ `! G0 i Q
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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;
: Q/ r7 `0 F m. {4 [: x2.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)
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试错结论:5 n! a5 I0 b0 M: z
1.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). @6 Q4 C6 ~* N( T& i5 J5 f
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。# }$ a1 @( x- {3 M8 V9 Y
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)。# S- R! p, O8 O
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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:
5 ^# |2 j) ~% w7 i }% ]1.如何解释模型搭建、报错和试错结论?
1 U V0 Z! s( p- Q3 f8 ~2.Simulink仿真的逻辑?2 p- l0 v4 [& v1 z1 f0 x
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