Passive anti-islanding-UVP/OVP and UFP/OFP passive anti-islanding model simulation based on simulink

目录

一、理论基础

二、案例背景

1.问题描述

2.思路流程

三、部分MATLAB程序

四、仿真结论分析

五、参考文献

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一、理论基础

      A perfect performance of photovoltaic (pv) grid power generation system,Need all kinds of protection measures to ensure the personal safety of users,At the same time prevent equipment damage caused by accident.Because of photovoltaic power generation systems and power grid parallel operation,So photovoltaic power generation system to timely detect the grid fault and cut off their connection with power grid.If the grid failure cannot be detected in time,There will be situations where the photovoltaic power generation system still supplies power to the local grid.,so that the local load is still powered,equipment damage and personal injury.This phenomenon is called the islanding effect.

       At present, island detection is mainly divided into passive detection and active detection..Passive detection is to use the power grid,Inverter output power and partial load power imbalance caused by the voltage of the inverter output value as the basis of islanding detection and frequency change.It has a simple detection method,No interference to system operation, etc..But if at the moment of power outage,Inverter output power is balanced with local load power,This method will not work. 

      Active detection is when the system works,output current to the inverter、Frequency or phase to apply a certain perturbation signal,并对其进行检测.If the grid is normal,Due to the huge balancing effect of the power grid,Is not affected by disturbance signal of the inverter output;Once the grid fails,These disturbances are gradually accumulated at the inverter output,until it exceeds the specified range,to reflect grid failure.Compared to passive detection methods,Active detection method with high precision,The advantage of small detection blind spot.But when there are multiple distributed energy systems in the local grid,Active detection is less effective,even ineffective in severe cases.
        Passive detection mainly includes voltage and frequency detection、相位检测、Three methods of frequency detection,There are certain applications in practice.However, due to the passive islanding detection method, there are higher requirements on whether the output power of the inverter matches the load power.,Therefore, there is a large detection blind area.Therefore, no detailed description will be given here..
       UVP/OVP和UFP/OVPThe detection algorithm judges by setting two gates,表达式如下所示：

     

     Can see from the above algorithm formula,但是由于UVP/OVP和UFP/OVPDetecting algorithm in larger scope limits,The detection blind spot is larger,在F和UThe detection range can only be detected by voltage and frequency..

二、案例背景

1.问题描述

首先,this power system,我们做如下的设置,即：

230V/50Hz,单相（single phase or 1 phase）.

    然后,The specific requirements for the simulation are：

负载：Small grid single phase 1kW grid-connected PV systems 

根据 IEEE 1547 standard Requirements for Anti-Islanding

·Voltage： 240V ± 10%, 

·frequency：50Hz ± 1%

·Quality Factor, Qf:  Qf < 2.5 (Qf = 0 , 0.02,0.04, … , 2.4)

·Required Islanding detection time: tdetect<0.2s  and isolated to the load

·THD: <5%

2.思路流程

        The inverse model of the island,采用simulink进行建模,在matlab2010b中,建立仿真模型,其中UVP/OVP和UFP/OVPThe detection algorithm is embedded inmatlab封装,供simulink调用.

三、部分MATLAB程序

UVP/OVP和UFP/OVP检测算法matlab2010b程序如下：

function Out = UVP_OVP_up(In);
V     = In;
Level = 264;

if V > Level || abs(V-Level) <= 0.05
   Out = 1;
else
   Out = 0;
end

function Out = UFP_OFP_low(In);
V     = In;
Level = 49;

if V < Level || abs(V-Level) <= 0.05
   Out = 1;
else
   Out = 0;
end

function Out = UFP_OFP_up(In);
V     = In;
Level = 51;

if V > Level || abs(V-Level) <= 0.05
   Out = 1;
else
   Out = 0;
end

function Out = UVP_OVP_low(In);
V     = In;
Level = 216;

if V < Level || abs(V-Level) <= 0.05
   Out = 1;
else
   Out = 0;
end

simulink整体模型如下：

四、仿真结论分析

       从仿真结果可知,采用UVP/OVP & UFP/OFPThis proactive approach to anti-islanding,The system can detect islands faster,同时,Little effect on the waveform of the whole system performance,but passiveAnti-island（anti-Islanding）方式,It has a large blind spot.

五、参考文献

[1] Zeineldin H H ,  Kirtley J . Performance of the OVP/UVP and OFP/UFP method with voltage and frequency dependent loads[J]. IEEE Transactions on Power Delivery, 2009, 24(2):772-778.A2-12