|
|
楼主 |
发表于 2014-12-31 11:34:51
|
显示全部楼层
本帖最后由 shanby 于 2014-12-31 11:45 编辑 : w f/ ]2 O# g
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 ...
6 q+ \" Y! |" j0 q/ O5 Y: Qshanby 发表于 2014-12-21 21:06
1 x, M9 A3 z9 C( t' w
9 X u/ ] n X, O8 n! |; ^) L$ h+ M: q$ E5 j; W/ z
查看如下帮助文档:Assumptions
Q; G( n9 O( x |' `" Q3 a- QThe 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
# [$ Z; w; W/ G) K/ LWhen 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.' [0 {8 z" ], B- w
$ _& s" ?* s& L, C# v5 L9 W* d( b7 v得出:
. Y, c; @# p( v: J. }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;/ p* p( G( {/ S1 c% g
2.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)
4 n! _; o# M7 `' f h6 o x: t; `5 B
试错结论:
1 a! k4 W3 | j' E1.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)4 B" f) T' ?4 R
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。+ ]* x; R: x9 i% `4 ?* V7 A
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)。. H+ q: I0 D* t! X& Y4 ?
0 T- T& Y0 s1 N% h1 _& m7 Q: G5 I
ShortCurrentFor300MW2.rar
(9.71 KB, 下载次数: 1)
; ` D! W* {* V
电压波形
4 A6 N- q$ Q" I# a7 F$ o9 [ p h: d7 E7 @
疑问:
2 ]8 l: q2 I+ V1.如何解释模型搭建、报错和试错结论?9 n3 y. }/ _9 }9 t
2.Simulink仿真的逻辑?, R; ~& R; C+ u; j( K/ J b7 z
6 n6 Y, l" j6 P6 U) q9 Y+ b
; u6 @+ a# O( c1 j( Q/ t t7 x |
|