TWI418809B - Isolation operation detection method for mains voltage control type electric energy converter - Google Patents
Isolation operation detection method for mains voltage control type electric energy converter Download PDFInfo
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本發明係關於一種市電併聯型電壓控制式電能轉換器之孤島運轉偵測方法，尤其是指一種僅在分散式發電系統所產生之電能與總負載所消耗之電能平衡或電力系統故障時，才對電壓控制式電能轉換器之輸出電壓進行擾動，以判斷是否發生孤島運轉之偵測方法。The invention relates to a method for detecting an island operation of a commercial parallel voltage-controlled power converter, in particular to a power balance between a power generated by a distributed power generation system and a total load or a power system failure. The output voltage of the voltage-controlled power converter is perturbed to determine whether or not an islanding operation detection method occurs.
小型發電系統或再生能源發電系統(如太陽能發電、風力發電、燃料電池發電等)，可視之為一分散式發電系統，這些分散式發電系統可被併聯至市電電源系統，以供電至負載。由於分散式發電系統與市電電源系統併聯運作時，必須有相關的保護機制，以確保運作時的安全性，其中「孤島運轉偵測」即是其中一種必要之保護機制。孤島運轉偵測係在市電電源系統因故障或維護等原因而切離時，分散式發電系統持續供電而形成，此孤島運轉現象將嚴重危害維修市電電源系統人員的安全與損壞電力設備。Small-scale power generation systems or renewable energy power generation systems (such as solar power, wind power, fuel cell power generation, etc.) can be regarded as a decentralized power generation system. These distributed power generation systems can be connected in parallel to the mains power system to supply power to the load. Since the decentralized power generation system operates in parallel with the mains power supply system, it must have relevant protection mechanisms to ensure the safety during operation. Among them, "island operation detection" is one of the necessary protection mechanisms. The island operation detection system is formed when the mains power system is disconnected due to failure or maintenance, etc., and the distributed power generation system is continuously supplied with power. This island operation phenomenon will seriously damage the safety of the maintenance of the mains power system personnel and damage the power equipment.
因此，以下係簡略說明數件針對偵測孤島運轉的相關專利文獻。中華民國發明專利公告第I278635號係揭露一種主動式的「孤島偵測方法」，其利用對電力系統進行擾動，需要一高解析度之量測設備以偵測系統電壓頻率和大小之變動，再比較其前後差異並調整函數以決定一調整量，作為下次加入一微量之輸出電流頻率或是相位的變化量，再依系統電壓大小與系統電壓頻率來判斷是否發生孤島運轉。但此方法需對電力系統持續擾動，其有影響電力品質之缺點，且需高解析度量測設備，導致量測成本增加。Therefore, the following is a brief description of several related patent documents for detecting island operations. The Republic of China Invention Patent Bulletin No. I278635 discloses an active "island detection method" that utilizes a high-resolution measurement device to detect changes in the system voltage frequency and size by using the power system to perturb. Compare the difference between the front and back and adjust the function to determine an adjustment amount, as the next time to add a small amount of output current frequency or phase change, and then determine whether islanding occurs according to the system voltage and the system voltage frequency. However, this method requires continuous disturbance of the power system, which has the disadvantage of affecting the power quality, and requires high-resolution measurement and measurement equipment, resulting in an increase in measurement cost.
又如美國專利第7,275,002號(Islanding detection and protection method)，係揭露一種利用改變負相序電壓量來擾動電力系統，偵測系統電壓頻率之變化來判定是否發生孤島運轉，當電力系統斷電產生孤島運轉時，因注入負相序電壓，故使系統電壓產生頻率漂移，利用正迴授方式加快系統電壓頻率之漂移量，因而偵測出發生孤島運轉。但此方法需改變負相序電壓量來持續擾動電力系統，故只適用於三相電力系統，且對電力系統持續擾動，故亦影響到電力品質。Another example is the US Island Patent No. 7,275,002 (Islanding detection and protection method), which discloses a method of changing the negative phase sequence voltage to disturb the power system, detecting changes in the system voltage frequency to determine whether or not an island operation occurs, and when the power system is powered off. When the island is in operation, the voltage of the system voltage is shifted due to the injection of the negative phase sequence voltage, and the drift of the system voltage frequency is accelerated by the positive feedback method, thereby detecting the islanding operation. However, this method needs to change the negative phase sequence voltage to continuously disturb the power system, so it is only applicable to the three-phase power system, and the power system continues to be disturbed, thus affecting the power quality.
再如美國專利第7,106,564號(Devices and methods for detecting islanding operation of a static power source)，係先利用一電能轉換器與市電電壓鎖相，而電能轉換器所產生之電壓頻率與市電電壓頻率有些微的變化，並判斷此次電壓頻率與上次電壓頻率之變化量，若沒大於最小頻率變化量時，表示市電正常，則每週期將重新改變電能轉換器輸出電壓頻率；反之，若此次電壓頻率與上次電壓頻率變化量大於最小頻率變化量之設定值時，將會累積頻率變化量，將下次輸出電壓頻率變動量與上次相加，再次偵測市電頻率是否正常，若市電頻率超出正常值範圍時，表示發生孤島運轉。但此方法同樣是對電力系統持續擾動，故會影響到電力品質。In the case of the device and methods for detecting islanding operation of a static power source, the power converter is first phase-locked with the mains voltage, and the voltage frequency generated by the power converter is slightly different from the mains voltage. Change, and judge the change of the voltage frequency and the previous voltage frequency. If it is not greater than the minimum frequency change, it means that the mains is normal, then the cycle of the output voltage of the power converter will be changed again every cycle; When the frequency and the previous voltage frequency change amount are greater than the set value of the minimum frequency change amount, the frequency change amount will be accumulated, and the next output voltage frequency variation amount will be added to the last time, and the mains frequency will be detected again if the mains frequency is normal. When the normal value range is exceeded, it indicates that island operation has occurred. However, this method is also a continuous disturbance to the power system, which will affect the power quality.
由於目前已知的主動式孤島運轉偵測方法，皆需要對電力系統進行持續性地擾動，故會影響電力系統之電力品質，有鑑於此，本發明之主要目的係提供一種市電併聯型電壓控制電能轉換器之孤島運轉偵測方法，在電力系統正常且分散式發電系統所產生之電能與總負載所消耗之電能不平衡時，電壓控制式電能轉換器之輸出電壓並不會對電力系統進行擾動；反之，只有在分散式發電系統所產生之電能與總負載所消耗之電能平衡或電力系統故障時，電壓控制式電能轉換器之輸出電壓才會對電力系統進行擾動，以判斷是否發生孤島運轉。Since the currently known active island operation detection method requires continuous disturbance of the power system, which affects the power quality of the power system, the main object of the present invention is to provide a commercial power parallel voltage control. The islanding operation detection method of the power converter, when the power generated by the normal and distributed power generation system of the power system is unbalanced with the power consumed by the total load, the output voltage of the voltage controlled power converter is not performed on the power system. Disturbance; conversely, the output voltage of the voltage-controlled power converter will perturb the power system to determine whether an island is generated only when the power generated by the distributed power generation system is balanced with the power consumed by the total load or the power system is faulty. Running.
為達成前述目的，本發明市電併聯型電壓控制式電能轉換器之孤島運轉偵測方法係包含：將一分散式發電系統連接至一市電電源，並供電給一負載，該分散式發電系統包含有一直流電源及一電壓控制式電能轉換器，其提供一基本實功率至該市電電源；若市電電源之市電電壓與電壓控制式電能轉換器之輸出電壓相減後之值其絕對值大於一預先設定誤差值，則判定該市電電源為正常，令一孤島偵測擾動信號設定為零，該電壓控制式電能轉換器輸出電壓不產生孤島偵測擾動；及若該市電電源端電壓與該電壓控制式電能轉換器之輸出電壓相減後之值其絕對值小於該預先設定誤差值，令該電壓控制式電能轉換器產生一孤島偵測擾動信號，並重新偵測該市電電源端電壓與該電壓控制式電能轉換器輸出電壓並相減後取其絕對值，再次判斷該絕對值是否仍小於該預先設定誤差值，若該絕對值仍小於該預先設定誤差值，即判斷為發生孤島運轉現象，並將該市電電源與分散式發電系統解聯。To achieve the foregoing objective, the islanding operation detecting method of the commercial parallel voltage-controlled power converter of the present invention comprises: connecting a distributed power generation system to a mains power supply, and supplying power to a load, the distributed power generation system including A DC power supply and a voltage controlled power converter provide a basic real power to the mains power supply; if the mains voltage of the mains power supply and the output voltage of the voltage controlled power converter are subtracted, the absolute value thereof is greater than a preset value The error value determines that the mains power supply is normal, so that an island detecting disturbance signal is set to zero, the voltage control type power converter output voltage does not generate an island detecting disturbance; and if the mains power terminal voltage and the voltage control type The absolute value of the output voltage of the power converter is less than the preset error value, so that the voltage-controlled power converter generates an island detecting disturbance signal, and re-detects the voltage of the utility power terminal and the voltage control The output voltage of the power converter is subtracted and its absolute value is taken, and it is judged again whether the absolute value is still less than the pre- Set an error value, if the absolute value of the error is still less than the predetermined value, it is determined that islanding operation occurs, and the mains supply and the disintegrin dispersion type power generating system.
本發明之另一目的係提供Another object of the present invention is to provide
一種市電併聯型電壓控制式電能轉換器之孤島運轉偵測方法，係應用於具有一市電電源、一分散式發電系統及一負載之電力系統，該市電電源經由一第一電磁開關與一連結電感串聯並連接至該負載，該分散式發電系統則經由一第二電磁開關連接該負載且包含有一直流電源與一電壓控制式電能轉換器，該方法包含：An island running detection method for a commercial parallel voltage-controlled power converter is applied to a power system having a mains power supply, a distributed power generation system and a load, the mains power supply via a first electromagnetic switch and a connected inductor Connected in series and connected to the load, the distributed power generation system is connected to the load via a second electromagnetic switch and includes a DC power supply and a voltage controlled power converter, the method comprising:
a.偵測該市電電源之市電電壓與該電壓控制式電能轉換器之輸出電壓；a. detecting a mains voltage of the mains power supply and an output voltage of the voltage controlled power converter;
b.將該市電電壓與該電壓控制式電能轉換器之輸出電壓相減並取其絕對值，判斷該絕對值是否大於一預先設定誤差值；b. subtracting the mains voltage from the output voltage of the voltage-controlled power converter and taking an absolute value thereof, and determining whether the absolute value is greater than a predetermined error value;
c.若該絕對值大於該預先設定誤差值，則將一孤島偵測擾動信號設定為零，並控制該第一電磁開關與第二電磁開關閉合，使市電電源及分散式發電系統與該負載連接，並回歸前述步驟a；c. If the absolute value is greater than the preset error value, set an island detection disturbance signal to zero, and control the first electromagnetic switch and the second electromagnetic switch to close, so that the mains power supply and the distributed power generation system and the load Connect and return to the aforementioned step a;
d.若該絕對值小於該預先設定誤差值，將孤島偵測擾動信號設定不為零，並再次重新偵測該市電電源之市電電壓與該電壓控制式電能轉換器之輸出電壓；d. If the absolute value is less than the preset error value, the island detection disturbance signal is set to be non-zero, and the mains voltage of the mains power source and the output voltage of the voltage-controlled power converter are again detected again;
e.重新將該市電電壓與該電壓控制式電能轉換器之輸出電壓相減，並對兩者之差值取其絕對值，判斷該絕對值是否仍大於該預先設定誤差值；e. re-sampling the mains voltage and the output voltage of the voltage-controlled power converter, and taking the absolute value of the difference between the two to determine whether the absolute value is still greater than the preset error value;
f.若該絕對值大於該預先設定誤差值，係執行前述步驟c；f. If the absolute value is greater than the predetermined error value, the foregoing step c is performed;
g.若該絕對值小於該預先設定誤差值，係判定為發生孤島運轉，並控制該第一電磁開關與第二電磁開關打開，令市電電源及分散式發電系統與該負載斷離。g. If the absolute value is less than the preset error value, it is determined that the islanding operation occurs, and the first electromagnetic switch and the second electromagnetic switch are controlled to be turned on, so that the commercial power source and the distributed power generation system are disconnected from the load.
藉由前述技術手段，本發明於市電電源正常供電而分散式發電系統所產生之電能和負載所消耗總電能未達到平衡時，該電壓控制式電能轉換器不會加入一孤島偵測擾動信號，以維持良好的供電品質，保持較低總諧波失真率。According to the foregoing technical means, when the power supply of the mains power supply is normal and the power generated by the distributed power generation system and the total power consumed by the load are not balanced, the voltage control type power converter does not add an island detecting disturbance signal. To maintain good power quality, maintain a low total harmonic distortion rate.
實際上，發生該分散式發電系統所產生電能與負載總消耗之電能達到功率平衡之機會極少，且發生之時間甚短，因此本發明所提出之孤島運轉偵測方法不但能準確偵測出孤島運轉，且不需要持續擾動電壓控制式電能轉換器之輸出電壓，所以可大幅減少擾動分散式發電系統之時間與次數，以維持良好的供電品質。In fact, there is very little opportunity for the power generated by the distributed power generation system to reach the power balance of the total energy consumed by the load, and the occurrence time is very short. Therefore, the island operation detection method proposed by the present invention can accurately detect the islands. It does not need to continuously disturb the output voltage of the voltage-controlled power converter, so the time and number of disturbances of the distributed power generation system can be greatly reduced to maintain good power quality.
再者，市電電源異常時時，電壓控制式電能轉換器透過輸出電壓擾動，亦可有效的判斷出是否發生孤島運轉現象。Furthermore, when the mains power supply is abnormal, the voltage-controlled power converter is disturbed by the output voltage, and it is also possible to effectively determine whether or not the islanding operation occurs.
請參考第一圖所示，本發明係應用於此電源系統架構，該電源系統主要包含一市電電源(10)、一分散式發電系統(20)、一負載(30)、一第一電磁開關(40)、一第二電磁開關(50)及一連結電感(60)。其中分散式發電系統(20)包含一直流電源(21)與一電壓控制式電能轉換器(22)，該市電電源(10)經由該第一電磁開關(40)及連結電感(60)串連而連接至該負載(30)，該分散式發電系統(20)則經由該第二電磁開關(50)連接至該負載(30)。Referring to the first figure, the present invention is applied to the power system architecture. The power system mainly includes a mains power supply (10), a distributed power generation system (20), a load (30), and a first electromagnetic switch. (40), a second electromagnetic switch (50) and a connecting inductor (60). The distributed power generation system (20) comprises a DC power supply (21) and a voltage controlled power converter (22). The mains power supply (10) is connected in series via the first electromagnetic switch (40) and the connecting inductor (60). Connected to the load (30), the distributed power generation system (20) is connected to the load (30) via the second electromagnetic switch (50).
本發明所提出孤島運轉偵測方法之技術特點除了有效偵測出孤島運轉以外，與其它主動式偵測孤島運轉方法最大不同即在於，當市電電源(10)正常且有能量進出市電電源(10)時，分散式發電系統(20)並不會對電力系統進行擾動，可提高整體電力品質；反之，本發明之孤島偵測技術只有在市電電源(10)斷電或當分散式發電系統(20)所產生之電能恰巧等於該負載(30)所消耗電能時，才會於電壓控制式電能轉換器(22)之輸出電壓加入一孤島偵測擾動信號△V來判斷是否發生孤島運轉，其基本原理說明如下：本發明分散式發電系統之孤島運轉偵測方法係由該電壓控制式電能轉換器(22)所實現，請參考第二圖所示為該電壓控制式電能轉換器(22)之控制方塊，該電壓控制式電能轉換器(22)為一電壓控制式直流/交流電能轉換器，其輸出電壓之參考信號經由計算而得到。若市電電壓可表示為：The technical features of the islanding operation detection method proposed by the present invention are different from other active detection island operation methods except that the islanding operation is effectively detected, that is, when the commercial power source (10) is normal and there is energy to enter and exit the utility power source (10) When the distributed power generation system (20) does not disturb the power system, the overall power quality can be improved; conversely, the islanding detection technique of the present invention is only when the mains power supply (10) is powered off or when the distributed power generation system ( 20) When the generated electric energy happens to be equal to the power consumed by the load (30), an island detecting disturbance signal ΔV is added to the output voltage of the voltage controlled power converter (22) to determine whether or not islanding operation occurs. The basic principle is as follows: The islanding operation detection method of the distributed power generation system of the present invention is implemented by the voltage control type power converter (22), please refer to the second figure for the voltage control type power converter (22) The control block, the voltage controlled power converter (22) is a voltage controlled DC/AC power converter, and the reference signal of the output voltage is obtained through calculation. If the mains voltage can be expressed as:
v s (t )=V s sin(ωt ) (1) v s ( t )= V s sin(ω t ) (1)
期望該電壓控制式電能轉換器(22)之控制使市電電源之市電電流為純弦波，且功率因數達到單位功因，則市電電流可表示為It is expected that the control of the voltage-controlled power converter (22) causes the mains current of the mains power source to be a pure sine wave, and the power factor reaches a unit power factor, the mains current can be expressed as
i s (t )=±I s 1 sin(ωt ) (2) i s ( t )=± I s 1 sin(ω t ) (2)
在第(2)式中，+I s 1 定義為該市電電流與市電電壓同相位，而實功電力潮流從市電電源(10)經由連結電感(60)流向電壓控制式電能轉換器(22)。相對的，-I s 1 定義為市電電流與市電電壓相位相反(互差180度)，實功電力潮流從電壓控制式電能轉換器(22)經由連結電感(60)流入市電電源(10)中。因此電壓控制式電能轉換器(22)之輸出電壓V C 可表示為：In the formula (2), + I s 1 is defined as the mains current is in phase with the mains voltage, and the actual power flow flows from the mains supply (10) to the voltage controlled electric energy converter via the connected inductor (60) (22) . In contrast, - I s 1 is defined as the opposite of the mains current and the mains voltage phase (180 degrees difference), and the actual power flow flows from the voltage-controlled power converter (22) into the mains supply (10) via the connected inductor (60). . Therefore, the output voltage V C of the voltage controlled power converter (22) can be expressed as:
從第(3)式中可知，不論實功之電力潮流方向為何，連結電感(60)兩端電壓與市電電壓皆相互垂直，故稱連結電感(60)兩端電壓為一垂直電壓，電壓控制式電能轉換器(22)之輸出電壓V C 可從市電電壓減去該垂直電壓來獲得。市電電壓可由一第一電壓檢出器(705)直接量測得到，而連結電感(60)兩端電壓之相位也已經確認固定，因此尚未確認之參數為該連結電感(60)之兩端電壓振幅大小。從第(3)式中，連結電感(60)端電壓之振幅與流經市電電流之振幅成比例，而市電電源(10)實功之電力潮流大小又與市電電流振幅大小成比例，故該連結電感(60)端電壓之振幅將決定市電電源(10)實功之電力潮流大小。It can be seen from the formula (3) that regardless of the direction of the power flow of the actual power, the voltage across the connected inductor (60) and the mains voltage are perpendicular to each other, so the voltage across the connected inductor (60) is a vertical voltage, and the voltage is controlled. The output voltage V C of the power converter (22) can be obtained by subtracting the vertical voltage from the mains voltage. The mains voltage can be directly measured by a first voltage detector (705), and the phase of the voltage across the connected inductor (60) has also been confirmed to be fixed, so the unconfirmed parameter is the voltage across the connected inductor (60). The magnitude of the amplitude. From the formula (3), the amplitude of the voltage at the end of the connected inductor (60) is proportional to the amplitude of the current flowing through the mains, and the magnitude of the power flow of the mains supply (10) is proportional to the magnitude of the mains current, so The amplitude of the voltage at the end of the connected inductor (60) will determine the power flow of the utility power supply (10).
根據第(3)式中可看出，市電電壓減去連結電感(60)端電壓即可獲得電壓控制式電能轉換器(22)之輸出電壓V C 之參考信號，其中，市電電壓可由該第一電壓檢出器(705)直接偵測獲得，而連結電感(60)端電壓為一純弦波電壓，並且與市電電壓相互垂直。According to the formula (3), the reference voltage of the output voltage V C of the voltage-controlled power converter (22) can be obtained by subtracting the voltage of the connected inductor (60) from the mains voltage, wherein the mains voltage can be obtained by the A voltage detector (705) is directly detected and the voltage at the junction inductor (60) is a pure sine wave voltage and is perpendicular to the mains voltage.
偵測到的市電電壓經由一帶通濾波器(706)處理，該帶通濾波器(706)之中心頻率與市電電壓基本波頻率相同，目的是為了濾除市電電壓中所含之諧波成份。帶通濾波器(706)之輸出經由一相移電路(707)產生一落後90度之電壓信號輸出，而相移電路(707)所產生之電壓波形就是該連結電感(60)端電壓之波形。為了避免以複雜的運算方式來計算負載(30)所消耗的實功量與該分散式發電系統(20)所產生之實功量，藉由調整電壓控制式電能轉換器(22)之一直流匯流排電壓(23)可獲取該連結電感(60)端電壓之振幅。The detected mains voltage is processed by a bandpass filter (706) whose center frequency is the same as the mains voltage fundamental frequency, in order to filter out the harmonic components contained in the mains voltage. The output of the band pass filter (706) generates a voltage signal output of 90 degrees behind via a phase shift circuit (707), and the voltage waveform generated by the phase shift circuit (707) is the waveform of the voltage of the connected inductor (60). . In order to avoid calculating the actual amount of work consumed by the load (30) and the amount of real work generated by the distributed power generation system (20) in a complicated calculation manner, by adjusting a DC of the voltage controlled power converter (22) The bus voltage (23) can obtain the amplitude of the voltage at the terminal of the connected inductor (60).
利用一第二電壓檢出器(700)偵測電壓控制式電能轉換器(22)之直流匯流排電壓(23)，利用一減法器(701)將直流匯流排電壓(23)減掉一直流匯流排設定電壓，其所產生之誤差信號再送往一比例積分控制器(702)，該直流匯流排設定電壓是考慮於穩態時，該電壓控制式電能轉換器(22)所需之直流匯流排電壓(23)大小而設定。本發明在發生孤島運轉時會產生一孤島偵測擾動信號ΔV ，此孤島偵測擾動信號即第二圖所示之孤島偵測擾動信號ΔV ，若市電電壓Vs與電壓控制式電能轉換器(22)之輸出電壓V C 相減後之值取其絕對值，若該絕對值大於一預先設定誤差值時，則該孤島偵測擾動信號ΔV 為零；反之，若市電電壓Vs與電壓控制式電能轉換器(22)之輸出電壓V C 相減後之值其絕對值小於預先設定誤差值時，即輸出孤島偵測擾動信號ΔV 。A DC voltage detector (700) is used to detect the DC bus voltage (23) of the voltage controlled power converter (22), and a DC bus (23) is subtracted from the DC bus by a subtractor (701). The busbar sets the voltage, and the error signal generated by the bus is sent to a proportional integral controller (702), which is a DC required for the voltage controlled power converter (22) in consideration of steady state. Set the busbar voltage (23) size. The present invention occurs when the islanding operation detecting islanding generates a disturbance signal Δ V, this island detecting islanding disturbance signal shown in FIG i.e., the second disturbance detection signal Δ V, if the utility voltage Vs and the voltage control type power converter (22) The value of the output voltage V C is subtracted from the absolute value. If the absolute value is greater than a predetermined error value, the island detecting disturbance signal Δ V is zero; otherwise, if the commercial voltage Vs and voltage When the absolute value of the output voltage V C of the control type power converter (22) is less than the preset error value, the island detecting disturbance signal Δ V is output.
此孤島偵測擾動信號ΔV 藉由一加法器(704)與比例積分控制器(702)之輸出信號相加，該加法器(704)之輸出為連結電感(60)端電壓之振幅大小。相移電路(707)之輸出信號與連結電感(60)端電壓之振幅信號經由一乘法器(708)相乘，以獲得連結電感(60)端電壓。This islanding detection of the disturbance signal Δ V output signals are summed by an adder (704) and a proportional integral controller (702), the adder (704) connected to the output inductor (60) end of the voltage amplitude. The output signal of the phase shift circuit (707) and the amplitude signal of the voltage at the terminal of the coupled inductor (60) are multiplied by a multiplier (708) to obtain the voltage at the junction inductor (60).
將乘法器(708)輸出之連結電感(60)端電壓與市電電源(10)經由該第一電壓檢出器(705)檢測出之電壓信號一併輸入至一減法器(709)相減，以獲得一參考信號，再將此參考信號與經由一第三電壓檢出器(710)對該電壓控制式電能轉換器(22)之輸出電壓檢測所獲得之電壓信號利用一減法器(711)相減，減法器(711)所獲得的誤差信號送至一波形控制器(712)，將波形控制器(712)輸出信號輸入至一脈寬調變及驅動電路(713)以驅動電壓控制式電能轉換器(22)之電力電子開關。The voltage of the connected inductor (60) outputted by the multiplier (708) is subtracted from the voltage signal detected by the commercial power source (10) via the first voltage detector (705), and input to a subtractor (709). Obtaining a reference signal, and using the reference signal and the voltage signal obtained by detecting the output voltage of the voltage-controlled power converter (22) via a third voltage detector (710) using a subtractor (711) Subtract, the error signal obtained by the subtractor (711) is sent to a waveform controller (712), and the waveform controller (712) output signal is input to a pulse width modulation and driving circuit (713) to drive the voltage control type. Power electronic switch for power converter (22).
請參考第三圖所示，為本發明之孤島運轉偵測方法流程圖，其主要步驟如下：偵測市電電源(10)之市電電壓Vs與電壓控制式電能轉換器(22)之輸出電壓V C (81)；判斷市電電源(10)之市電電壓Vs與電壓控制式電能轉換器(22)之輸出電壓V C 相減後之值其絕對值是否大於一預先設定誤差值Verr(82)；若市電電源(10)之市電電壓Vs與電壓控制式電能轉換器(22)之輸出電壓V C 相減後之值其絕對值大於該預先設定誤差值Verr時，則連結電感(60)端電壓將不會被改變，此時，孤島偵測擾動信號△V設定為零，第一與第二電磁開關(40)(50)閉合(86)，電壓控制式電能轉換器(22)不產生電壓擾動信號並持續運轉；反之，若市電電源(10)之市電電壓Vs與電壓控制式電能轉換器(22)之輸出電壓V C 相減後之值其絕對值小於該預先設定誤差值Verr時，則孤島偵測擾動信號ΔV 不等於零(83)，此將會加入垂值電壓之振幅，而該預先設定誤差值Verr是為了避免量測上的誤差，其值非常小但不等於零，因此，將孤島偵測擾動信號ΔV 加入連結電感(60)端電壓之振幅；重新偵測市電電壓Vs與電壓控制式電能轉換器(22)之輸出電壓V C (84)；判斷市電電源(10)之市電電壓Vs與電壓控制式電能轉換器(22)之輸出電壓V C 相減後之值其絕對值是否大於該預先設定誤差值Verr(85)；若市電電源(10)之市電電壓Vs與電壓控制式電能轉換器(22)之輸出電壓V C 相減後之值其絕對值大於預先設定誤差值Verr時，表示目前市電電源(10)正常，只是分散式發電系統(20)所產生之電能恰巧與負載所消耗的總電能相等，因此，孤島偵測擾動信號ΔV 設定為零，第一與第二電磁開關(40)(50)維持閉合(86)，電壓控制式電能轉換器(22)輸出不產生電壓擾動並持續運轉；反之，經由加入不等於零之孤島偵測擾動信號ΔV 後，若市電電源(10)之市電電壓Vs與電壓控制式電能轉換器(22)之輸出電壓V C 相減後之值其絕對值仍然小於該預先設定誤差值Verr時，表示偵測出該分散式發電系統(20)正處於孤島運轉中，因此將第一與第二電磁開關(40)(50)打開(87)，使分散式發電系統(20)切離市電電源(10)，並切離負載(30)，停止系統運轉。Please refer to the third figure, which is a flow chart of the island operation detection method according to the present invention. The main steps are as follows: detecting the mains voltage Vs of the mains power supply (10) and the output voltage V of the voltage controlled electric energy converter (22). C (81); determining whether the value of the mains voltage Vs of the mains power supply (10) and the output voltage V C of the voltage controlled electric energy converter (22) is greater than a predetermined error value Verr (82); If the value of the mains voltage Vs of the commercial power supply (10) and the output voltage V C of the voltage-controlled power converter (22) are subtracted from the preset value of the error value Verr, the voltage of the inductor (60) is connected. Will not be changed, at this time, the island detection disturbance signal ΔV is set to zero, the first and second electromagnetic switches (40) (50) are closed (86), and the voltage-controlled power converter (22) does not generate voltage. Disturbing the signal and continuing to operate; conversely, if the value of the mains voltage Vs of the commercial power supply (10) and the output voltage V C of the voltage controlled power converter (22) are subtracted from the preset value of the error value Verr, detecting the islanding disturbance signal Δ V is not equal to zero (83), this value will be added to the vertical electrical The amplitude, which is set in advance in order to avoid error Verr error in the measurement, which value is very small but not equal to zero, therefore, the terminal voltage amplitude detecting islanding disturbance signal Δ V added coupling inductance (60); re-detect Measure the mains voltage Vs and the output voltage V C of the voltage-controlled power converter (22) (84); determine the mains voltage Vs of the mains supply (10) and the output voltage V C of the voltage-controlled power converter (22) Whether the absolute value is greater than the preset error value Verr (85); if the mains voltage Vs of the commercial power supply (10) is subtracted from the output voltage V C of the voltage controlled power converter (22), the absolute value is absolute when the value is larger than a preset error value Verr is, that the current mains supply (10) normal, power is only distributed power generation system (20) arising happens to be equal to the total energy consumed by the load, and therefore, the signal Δ V is set islanding detection disturbances Zero, the first and second electromagnetic switches (40) (50) remain closed (86), the voltage-controlled power converter (22) output does not generate voltage disturbances and continues to operate; conversely, by adding islands not equal to zero detection after the disturbance signal Δ V, if When the absolute value of the electric power supply (10) of the mains voltage Vs and the voltage control type power converter (22) of the output voltage value V C remains after the subtraction is smaller than the predetermined error value Verr, represents the distributed power generation detect The system (20) is in an island operation, so the first and second electromagnetic switches (40) (50) are opened (87), the distributed power generation system (20) is cut off from the mains power supply (10), and the load is cut off. (30) Stop the system operation.
本發明所提出的孤島運轉偵測方法係在該連結電感(60)端電壓幾乎等於零的時候，加入一不等於零之電壓振幅擾動量ΔV 以破壞整體系統功率平衡，如果市電電壓與電壓控制式電能轉換器(22)之輸出電壓其壓差仍小於一預先設定誤差值Verr時，將可偵測出發生孤島運轉，此也表示經過垂直電壓一振幅擾動量來破壞實功平衡後，介於市電電源(10)與電壓控制式電能轉換器(22)間之連結電感(60)依然沒有電流流動。因此，本發明所提出之孤島偵測方法在最困難偵測的情況下，依然能有效偵測出孤島運轉。The proposed invention islanding operation detecting method based on when the coupling inductance (60) the terminal voltage is almost zero, adding the amplitude perturbation voltage not equal to zero of Δ V to disrupt the overall system power balance, if the mains voltage and the voltage-controlled When the output voltage of the power converter (22) is still less than a preset error value Verr, the islanding operation can be detected, which also means that after the vertical voltage-amplitude disturbance amount is broken to break the real power balance, There is still no current flowing between the connected inductor (60) between the mains power supply (10) and the voltage controlled power converter (22). Therefore, the island detecting method proposed by the present invention can effectively detect the islanding operation in the most difficult detection situation.
相較於傳統主動式孤島運轉偵測方法，本發明所提出孤島運轉偵測方法之優點在於當市電電源(10)正常供電而分散式發電系統(20)所產生之電能和負載(30)所消耗總電能未達到平衡時，該電壓控制式電能轉換器(22)並不會加入孤島偵測擾動信號，因此不會對市電電源(10)產生擾動，使市電電流波形可達到近似正弦波，並且與市電電壓同相位或相位相反(相差180度)，故不會為了偵測孤島運轉而影響電力品質。因此，本發明所提出之孤島運轉偵測方法，於市電電源(10)正常供電而分散式發電系統(20)所產生之電能和負載(30)所消耗總電能未達到平衡時，並無加入任何孤島偵測擾動信號，市電電流可一直保持較低總諧波失真率。Compared with the conventional active island operation detection method, the islanding operation detection method proposed by the present invention has the advantages of power and load (30) generated by the distributed power generation system (20) when the mains power supply (10) is normally powered. When the total power consumption is not balanced, the voltage-controlled power converter (22) does not add an island detection disturbance signal, so it does not cause disturbance to the commercial power supply (10), so that the mains current waveform can reach an approximate sine wave. Moreover, it is in phase or phase opposite to the mains voltage (180 degrees difference), so it does not affect the power quality in order to detect the operation of the island. Therefore, the islanding operation detecting method proposed by the present invention does not join when the mains power supply (10) is normally powered and the power generated by the distributed power generation system (20) and the total power consumed by the load (30) are not balanced. Any island detection disturbance signal, the mains current can always maintain a low total harmonic distortion rate.
實際應用上，發生分散式發電系統(20)所產生電能與負載(30)總消耗之電能達到功率平衡之機會極少，且發生之時間甚短，因此本案所提出孤島運轉偵測方法不但能準確偵測出孤島運轉，且不需要持續擾動電壓控制式電能轉換器(22)之輸出電壓，分散式發電系統(20)將會大幅減少擾動之時間與次數。In practical applications, there is very little opportunity for the power generated by the distributed power generation system (20) and the total energy consumed by the load (30) to reach a power balance, and the time of occurrence is very short. Therefore, the island operation detection method proposed in this case is accurate not only accurate. The island operation is detected and there is no need to continuously disturb the output voltage of the voltage controlled power converter (22). The distributed power generation system (20) will greatly reduce the time and number of disturbances.
以上所述者，皆僅為本發明之較佳實施例而已，並非用限定本發明實施之範圍。即凡依本發明之申請專利範圍由熟悉本案背景技藝之人士任施匠思而為諸般修飾，皆不脫離如申請專利範圍所欲保護者，而為本發明專利範圍所涵蓋。The above are only the preferred embodiments of the present invention and are not intended to limit the scope of the invention. That is, the scope of the patent application of the present invention is modified by those skilled in the art and is not intended to be protected by the scope of the patent application.
(10)．．．市電電源(10). . . Mains power
(20)．．．分散式發電系統(20). . . Decentralized power generation system
(21)．．．直流電源(twenty one). . . DC power supply
(22)．．．電壓控制式電能轉換器(twenty two). . . Voltage controlled power converter
(23)．．．直流匯流排電壓(twenty three). . . DC bus voltage
(30)．．．負載(30). . . load
(40)．．．第一電磁開關(40). . . First electromagnetic switch
(50)．．．第二電磁開關(50). . . Second electromagnetic switch
(60)．．．連結電感(60). . . Connecting inductance
(700)．．．第二電壓檢出器(700). . . Second voltage detector
(701)．．．減法器(701). . . Subtractor
(702)．．．比例積分控制器(702). . . Proportional integral controller
(704)．．．加法器(704). . . Adder
(705)．．．第一電壓檢出器(705). . . First voltage detector
(706)．．．帶通濾波器(706). . . Bandpass filter
(707)．．．相移電路(707). . . Phase shift circuit
(708)．．．乘法器(708). . . Multiplier
(709)．．．減法器(709). . . Subtractor
(710)．．．第三電壓檢出器(710). . . Third voltage detector
(711)．．．減法器(711). . . Subtractor
(712)．．．波形控制器(712). . . Waveform controller
(713)．．．脈寬調變及驅動電路(713). . . Pulse width modulation and drive circuit
第一圖：本發明市電電源系統與分散式發電系統架構圖。First: The architecture diagram of the mains power system and the distributed power generation system of the present invention.
第二圖：結合本發明分散式發電系統之孤島運轉偵測發方法之電壓控制式電能轉換器其控制方塊圖。Second: A control block diagram of a voltage controlled power converter incorporating the islanding operation detection method of the distributed power generation system of the present invention.
第三圖：本發明孤島運轉偵測方法之流程圖。Third: Flow chart of the method for detecting island operation in the present invention.
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| CN105067905A (en) * | 2015-07-17 | 2015-11-18 | 国家电网公司 | Frequency converter power electronics controllable loading method based on grid connected inverter |
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| TWI464994B (en) * | 2012-03-21 | 2014-12-11 | Univ Nat Sun Yat Sen | Distributed power generation system with seamlessly grid-connected transition and method for implementing grid-connected transition for distributed power generation system |
| CN102590713B (en) * | 2012-03-29 | 2014-06-04 | 浙江特雷斯电子科技有限公司 | Detection method of islanding effects with reactive current disturbance based on amplitude changes and device thereof |
| CN103018583B (en) * | 2012-08-03 | 2016-02-03 | 中国能源建设集团广东省电力设计研究院有限公司 | Verification method is selected based on MMC flexible direct-current transmission system level number |
| TWI477046B (en) * | 2012-09-26 | 2015-03-11 | Univ Nat Kaohsiung Applied Sci | Grid-connected photovoltaic generation system with positive grounding for solar cell arrays |
| US9520819B2 (en) | 2014-02-28 | 2016-12-13 | General Electric Company | System and method for controlling a power generation system based on a detected islanding event |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105067905A (en) * | 2015-07-17 | 2015-11-18 | 国家电网公司 | Frequency converter power electronics controllable loading method based on grid connected inverter |
| CN105067905B (en) * | 2015-07-17 | 2018-06-12 | 国家电网公司 | A kind of frequency converter power electronics controllable load method based on gird-connected inverter |
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| TW201126177A (en) | 2011-08-01 |
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