Gerilim bozulmalarının tarımsal sulamada kullanılan farklı besleme türlerine sahip asenkron motorlar üzerindeki etkilerinin araştırılması

Abstract

Türkiye’nin tarımsal arazilerin çok yüksek bir oranının mevcut olduğu GAP uygulama bölgesinin sulama ağı çok yetersizdir. Bu nedenle sulama işlemi, çiftçilerin kendi olanaklarıyla kurdukları, derin kuyulardan yer altı suyunun yüksek güçlü asenkron motorlar ile yeryüzüne çıkarıldığı tesislerle yapılmaktadır. Bu çalışmada sulama dönemlerinde şebekede meydana gelen gerilim dalgalanmalarının asenkron motorların performansı üzerindeki etkileri analiz edilmiştir. Bu etkilerin analizi için Türkiye’nin Güneydoğu Anadolu Bölgesinde Kızıltepe Ovasında tarımsal sulamanın yapıldığı bir tesis pilot olarak seçilmiştir. Ele alınan tesisi besleyen dağıtım hattındaki gerilim değişimleri kaydedilmiştir. Bu tesiste kullanılan pompa-asenkron motor grubu MATLAB/Simulink’te modellenmiş ve benzetim çalışması yapılmıştır. Benzetim çalışmalarında, dağıtım sisteminden kaydedilmiş gerilim bozulmalarının asenkron motorun performansı üzerindeki etkileri incelenmiştir. Motor-pompa grubu bozuk şebeke gerilimine doğrudan ve gerilim kaynaklı altı adımlı AC sürücü üzerinden bağlanarak motor çıkış parametreleri incelenmiştir. Sonuçlara bağlı olarak şebeke geriliminde dalgalanmayı azaltma yönünde asenkron motor sistemlerinde alınabilecek önlemler tartışılmıştır.

Keywords

• Asenkron motor, Gerilim dengesizliği, Değişken hızlı ac sürücü, Tarımsal sulama

Impacts of voltage distortion on used different feed types in induction motors for agricultural irrigation

Abstract

In the application field of Southeastern Anatolia Project (GAP) which consist approximately %20 of the economic irrigation area throughout Turkey, a large part of the irrigation projects was not completed. Roughly %15 of irrigation projects of GAP is in process. Inadequency of the irrigation structure which relies on the project, leaves farmers no choice but watering with their own ways. For that purpose, the asynchronous engines which have average 100 kw power are commonly used. Insufficiency of electricity distribution substructure, defective construction of pump-motor facilities according to engineering services and with the reason of lack of capacity in transmission system, important quality problems occur. The quality problems affect very high-tension lines and interconnected network, also. The most common quality problems of electiricity energy are power cuts and voltage disorders. The energy quality problems in network affect closely asynchronous engines. While this impact is reflected to the performances of the engines, it affects the network negatively because of the load characteristic of the asynchronous engine. Thus, the vicious cycle comes out of. One way to reduce the impacts of disorderedness of tension is feeding the asynchronous engine via a driver. The drivers of asynchronous engine are the systems which are used commonly in industry especially in the variable-speed applications. Variable-speed drivers are also used in pump-motor mechanism. These drivers have features like highdynamic performance, flexible usage and energy saving. The driver of asynchronous engines affect positively the system’s efficient functioning in critical tension disorderedness. In most of the tension disorderedness, voltage doesn’t go down under its nominal rate %70 and disorderedness lasts less then 300 ms. In these conditions of tension disorderedness, VSDs have ability to work without any loss of moment and without any power cut in speed control time. In this work, the situations of the 100kw asynchronous engines which work under disordered tension are analysed. To determine the performances of the asynchronous engines under changing tensions in the network, a pilot region is discussed. Depending on 34.5 kw distribution line, an irrigation facility which is feeding from Dikmen transformator center in Kızıltepe plain is chosen as a research area. The simulation model of asynchronous motor-pump mechanism which is used in watering, is created by the help of MATLAB simulink software. In the simulation model, real tension rates which is measured on the feeding distrubution line during watering time, are used. In the discussed irrigation facility asynchronous engines are given ways by connecting directly to the network, although it is not appropriate. That’s why this research analyses the asynchronous engines which are given way directly. Beside, it is discussed the same asynchronous engine’ feeding with six stepted driver which has a tension source. The analyze determines asynchronous engines’ the stator flows, electromagnetic moment, the speed of rotor and the changings of active and reactive powers which it absorbs from the network. In this way, under the measured disordered tension, the conduct of the asynchronous engine which is fed by direct and variable-speed driver, is analyzed. The performances of the used drivers on tension changes and the impact on the outputs of the system are studied and compared.

Keywords

• Induction motor, Voltage unbalanced, Variable speed ac driver, Agricultural irrigaion