Active distribution networks planning with integration of demand response

YesThis paper proposes a probabilistic method for active distribution networks planning with integration of demand response. Uncertainties related to solar irradiance, load demand and future load growth are modelled by probability density functions. The method simultaneously minimizes the total operational cost and total energy losses of the lines from the point of view of distribution network operators with integration of demand response over the planning horizon considering active management schemes including coordinated voltage control and adaptive power factor control. Monte Carlo simulation method is employed to use the generated probability density functions and the weighting factor method is used to solve the multi-objective optimization problem. The effectiveness of the proposed method is demonstrated with 16-bus UK generic distribution system

Pengaruh Gliserol dan Air Kelapa untuk Media Penyimpanan terhadap Motilitas dan Viabilitas Spermatozoa Ikan Nilem (Osteochilus Hasselti)

Penelitian ini bertujuan untuk mengetahui pengaruh perbedaan dosis gliserol dan air kelapa terhadap motilitas dan viabilitas spermatozoa ikan nilem yang disimpan dan Mengetahui dosis gliserol dan air kelapa terbaik sebagai media penyimpanan spermatozoa ikan nilem . Penelitian ini menggunakan rancangan acak lengkap (RAL) dengan 4 perlakuan dan 3 ulangan. Perlakuan yang diberikan berupa penambahan gliserol dan air kelapa dengan berbagai dosis, perlakuan yang diberikan P1 (0% gliserol + 100% air kelapa), P2 (25% gliserol + 75% air kelapa), P3 (50% gliserol + 50% air kelapa), P4 (75% gliserol + 25% air kelapa). Tahapan penelitian ini berupa Persiapan objek, alat dan bahan, pembuatan ekstender, preparasi sperma dari induk, penyimpanan sel spermatozoa, Pengamatan persentase motilitas dan viabilitas spermatozoa. Data yang diperoleh dianalisis secara statistik pada tingkat kepercayaan 95% menggunakan sidik ragam (ANOVA). Data yang mempunyai pengaruh nyata dilanjutkan dengan uji duncan. Hasil penelitian menunjukan bahwa dosis 25% gliserol + 75% air kelapa, 50% gliserol + 50% air kelapa, 75% gliserol + 25% air kelapa berpengaruh nyata terhadap motilitas dan viabilitas (P<0,05) namun dosis 0% gliserol + 100% air kelapa tidak memberi pengaruh nyata terhadap motilitas dan viabilitas

Steady State Operation and Control of Power Distribution Systems in the Presence of Distributed Generation [Elektronisk resurs]

In this thesis, the impact of distributed generation (DG) on steady state operation and control of power distribution systems is investigated. Over the last few years, a number of factors have led to an increased interest in DG schemes. DG is gaining more and more attention worldwide as an alternative to large-scale central generating stations.A number of DG technologies are in a position to compete with central generating stations. There are also likely opportunities for renewable energy technologies in DG. Indeed, some renewable energy based DG technologies are not yet generally cost-competitive. However, technology development may lead to major innovative progress in materials, processes, designs and products, with higher efficiency and cost reduction opportunities. In electric power systems with large central generating stations, the electric power flows in one way direction: from generation stations to transmission systems, then to distribution systems and finally to the loads. Therefore, distribution systems were designed as radial systems; and many operation and control in distribution systems, such as voltage control and protection, are based on the assumption that distribution systems are radial.In a radial distribution feeder, voltage decreases towards the end of the feeder, as loads cause a voltage drop. However, it will be altered with the presence of DG. DG will increase the voltage at its connection point, which in turn will increase the voltage profile along the feeder. This increase may exceed the maximum allowed voltage when the DG power is high. One way to mitigate this overvoltage is when DG absorbs reactive power from the grid. This method is effective for mitigation of overvoltage-caused DG in low voltage (LV) feeders where the mean of voltage control is obtained from an off-load tap changer. However, if DG absorbs reactive power, feeder losses will increase.The maximum DG that can be integrated in a feeder (DG integration limit) is limited by maximum allowed voltage variation, conductor thermal ampacity and upstream transformer rating. The DG integration limit is usually defined based on maximum DG and minimum load scenario. However, when DG and load power fluctuate throughout the day, this scenario will lead to unnecessary restriction of DG integration. Minimum load and maximum DG may not happen at the same time. Stochastic assessment using Monte Carlo simulations will be more reliable to determine the DG integration limit in this circumstance. In medium voltage (MV) feeder, where the voltage control is normally achieved by using on-load tap changer (LTC) and capacitor banks; the mitigation of overvoltage-caused DG can be obtained by coordinating DG with the LTC and capacitors. The use of line drop compensation (LDC), which is present in most LTCs but often not used, can also mitigate the overvoltage. When the LDC is coordinated properly with DGs, LDC will even extend the DG integration limit. The DG integration limit in a MV feeder can also be extended by allowing DG to absorb reactive power as in an LV feeder, or by installing a voltage regulator (VR). However, if DG absorbs reactive power, it means that the reactive power should be generated somewhere else in the system, and VR installation means investment cost. The DG integration limit can also be extended by operating the MV feeders in a meshed system (closed-loop). The expense of this meshed operation is that the protection of the feeder is more complicated. The presence of DG will obviously increase residual voltage (dip magnitude) during a short circuit. However, depending on the location of the DG relative to the protection device (PD) and fault, DG may shorten or lengthen the duration of the short circuit, which directly correlates to dip duration. This is because, the location of the DG relative to the PD and fault defines whether DG will increase or decrease the short circuit current sensed by PD. However, PDs in distribution systems are normally overcurrent (OC) based PDs, which clear the fault in a certain time delay depending on the short circuit current sensed by them. Thus, though DG increases dip magnitude, further investigation on coordination of voltage dip and OC protection is needed to investigate whether the DG will prevent sensitive equipment from tripping, due to voltage dip, or not.Protection coordination in distribution systems can be affected by the increasing or decreasing short circuit current sensed by PDs. Certain corrective actions are then needed. However, when the DG is not expected to be in islanding operation; DG still has to be disconnected from distribution systems every time a fault occurs, even if all corrective actions have been implemented. Disconnecting all DGs every time a temporary fault occurs would make the system very unreliable. This is especially because most of the faults in overhead distribution systems are temporary. Thus, when the DG is not expected to be in islanding operation, a protection scheme that can keep DG on line to supply the load during the fault is necessary. The scheme should ensure that the OC PDs in on the feeder can clear the fault without loosing their proper coordination

Studi Kasus Hipofungsi Ovari pada Kuda di Pulau Jawa dan Madura Tahun 2009-2015.

oai:repository.ipb.ac.id:123456789/84905Hipofungsi ovari sering terjadi pada kuda yang ditandai dengan tidak terjadinya siklus estrus. Studi ini dilakukan untuk mengetahui prevalensi kasus hipofungsi ovari pada kuda betina di Pulau Jawa dan Madura selama tahun 2009-2015. Pemeriksaan kondisi ovari kuda sebagai pasien dilakukan dengan ultrasonografi. Hasil yang ditemukan berupa ovari dengan folikel-folikel berukuran kecil tanpa disertai adanya corpus luteum pada kuda penderita. Sebanyak 179 ekor kuda didiagnosa mengalami hipofungsi ovari dari 3 373 ekor kuda yang diperiksa. Rata-rata prevalensi kasus per tahun adalah 5.16%. Pengobatan yang diberikan kepada penderita berupa injeksi vitamin A dan E atau injeksi gonadorelin dengan persentase kesembuhan sebesar 84.92% yang ditandai dengan kuda kembali mengalami siklus estrus

Steady State Operation and Control of Power Distribution Systems in the Presence of Distributed Generation

In this thesis, the impact of distributed generation (DG) on steady state operation and control of power distribution systems is investigated. Over the last few years, a number of factors have led to an increased interest in DG schemes. DG is gaining more and more attention worldwide as an alternative to large-scale central generating stations.A number of DG technologies are in a position to compete with central generating stations. There are also likely opportunities for renewable energy technologies in DG. Indeed, some renewable energy based DG technologies are not yet generally cost-competitive. However, technology development may lead to major innovative progress in materials, processes, designs and products, with higher efficiency and cost reduction opportunities. In electric power systems with large central generating stations, the electric power flows in one way direction: from generation stations to transmission systems, then to distribution systems and finally to the loads. Therefore, distribution systems were designed as radial systems; and many operation and control in distribution systems, such as voltage control and protection, are based on the assumption that distribution systems are radial.In a radial distribution feeder, voltage decreases towards the end of the feeder, as loads cause a voltage drop. However, it will be altered with the presence of DG. DG will increase the voltage at its connection point, which in turn will increase the voltage profile along the feeder. This increase may exceed the maximum allowed voltage when the DG power is high. One way to mitigate this overvoltage is when DG absorbs reactive power from the grid. This method is effective for mitigation of overvoltage-caused DG in low voltage (LV) feeders where the mean of voltage control is obtained from an off-load tap changer. However, if DG absorbs reactive power, feeder losses will increase.The maximum DG that can be integrated in a feeder (DG integration limit) is limited by maximum allowed voltage variation, conductor thermal ampacity and upstream transformer rating. The DG integration limit is usually defined based on maximum DG and minimum load scenario. However, when DG and load power fluctuate throughout the day, this scenario will lead to unnecessary restriction of DG integration. Minimum load and maximum DG may not happen at the same time. Stochastic assessment using Monte Carlo simulations will be more reliable to determine the DG integration limit in this circumstance. In medium voltage (MV) feeder, where the voltage control is normally achieved by using on-load tap changer (LTC) and capacitor banks; the mitigation of overvoltage-caused DG can be obtained by coordinating DG with the LTC and capacitors. The use of line drop compensation (LDC), which is present in most LTCs but often not used, can also mitigate the overvoltage. When the LDC is coordinated properly with DGs, LDC will even extend the DG integration limit. The DG integration limit in a MV feeder can also be extended by allowing DG to absorb reactive power as in an LV feeder, or by installing a voltage regulator (VR). However, if DG absorbs reactive power, it means that the reactive power should be generated somewhere else in the system, and VR installation means investment cost. The DG integration limit can also be extended by operating the MV feeders in a meshed system (closed-loop). The expense of this meshed operation is that the protection of the feeder is more complicated. The presence of DG will obviously increase residual voltage (dip magnitude) during a short circuit. However, depending on the location of the DG relative to the protection device (PD) and fault, DG may shorten or lengthen the duration of the short circuit, which directly correlates to dip duration. This is because, the location of the DG relative to the PD and fault defines whether DG will increase or decrease the short circuit current sensed by PD. However, PDs in distribution systems are normally overcurrent (OC) based PDs, which clear the fault in a certain time delay depending on the short circuit current sensed by them. Thus, though DG increases dip magnitude, further investigation on coordination of voltage dip and OC protection is needed to investigate whether the DG will prevent sensitive equipment from tripping, due to voltage dip, or not.Protection coordination in distribution systems can be affected by the increasing or decreasing short circuit current sensed by PDs. Certain corrective actions are then needed. However, when the DG is not expected to be in islanding operation; DG still has to be disconnected from distribution systems every time a fault occurs, even if all corrective actions have been implemented. Disconnecting all DGs every time a temporary fault occurs would make the system very unreliable. This is especially because most of the faults in overhead distribution systems are temporary. Thus, when the DG is not expected to be in islanding operation, a protection scheme that can keep DG on line to supply the load during the fault is necessary. The scheme should ensure that the OC PDs in on the feeder can clear the fault without loosing their proper coordination

Steady State Operation and Control of Power Distribution Systems in the Presence of Distributed Generation

In this thesis, the impact of distributed generation (DG) on steady state operation and control of power distribution systems is investigated. Over the last few years, a number of factors have led to an increased interest in DG schemes. DG is gaining more and more attention worldwide as an alternative to large-scale central generating stations.A number of DG technologies are in a position to compete with central generating stations. There are also likely opportunities for renewable energy technologies in DG. Indeed, some renewable energy based DG technologies are not yet generally cost-competitive. However, technology development may lead to major innovative progress in materials, processes, designs and products, with higher efficiency and cost reduction opportunities. In electric power systems with large central generating stations, the electric power flows in one way direction: from generation stations to transmission systems, then to distribution systems and finally to the loads. Therefore, distribution systems were designed as radial systems; and many operation and control in distribution systems, such as voltage control and protection, are based on the assumption that distribution systems are radial.In a radial distribution feeder, voltage decreases towards the end of the feeder, as loads cause a voltage drop. However, it will be altered with the presence of DG. DG will increase the voltage at its connection point, which in turn will increase the voltage profile along the feeder. This increase may exceed the maximum allowed voltage when the DG power is high. One way to mitigate this overvoltage is when DG absorbs reactive power from the grid. This method is effective for mitigation of overvoltage-caused DG in low voltage (LV) feeders where the mean of voltage control is obtained from an off-load tap changer. However, if DG absorbs reactive power, feeder losses will increase.The maximum DG that can be integrated in a feeder (DG integration limit) is limited by maximum allowed voltage variation, conductor thermal ampacity and upstream transformer rating. The DG integration limit is usually defined based on maximum DG and minimum load scenario. However, when DG and load power fluctuate throughout the day, this scenario will lead to unnecessary restriction of DG integration. Minimum load and maximum DG may not happen at the same time. Stochastic assessment using Monte Carlo simulations will be more reliable to determine the DG integration limit in this circumstance. In medium voltage (MV) feeder, where the voltage control is normally achieved by using on-load tap changer (LTC) and capacitor banks; the mitigation of overvoltage-caused DG can be obtained by coordinating DG with the LTC and capacitors. The use of line drop compensation (LDC), which is present in most LTCs but often not used, can also mitigate the overvoltage. When the LDC is coordinated properly with DGs, LDC will even extend the DG integration limit. The DG integration limit in a MV feeder can also be extended by allowing DG to absorb reactive power as in an LV feeder, or by installing a voltage regulator (VR). However, if DG absorbs reactive power, it means that the reactive power should be generated somewhere else in the system, and VR installation means investment cost. The DG integration limit can also be extended by operating the MV feeders in a meshed system (closed-loop). The expense of this meshed operation is that the protection of the feeder is more complicated. The presence of DG will obviously increase residual voltage (dip magnitude) during a short circuit. However, depending on the location of the DG relative to the protection device (PD) and fault, DG may shorten or lengthen the duration of the short circuit, which directly correlates to dip duration. This is because, the location of the DG relative to the PD and fault defines whether DG will increase or decrease the short circuit current sensed by PD. However, PDs in distribution systems are normally overcurrent (OC) based PDs, which clear the fault in a certain time delay depending on the short circuit current sensed by them. Thus, though DG increases dip magnitude, further investigation on coordination of voltage dip and OC protection is needed to investigate whether the DG will prevent sensitive equipment from tripping, due to voltage dip, or not.Protection coordination in distribution systems can be affected by the increasing or decreasing short circuit current sensed by PDs. Certain corrective actions are then needed. However, when the DG is not expected to be in islanding operation; DG still has to be disconnected from distribution systems every time a fault occurs, even if all corrective actions have been implemented. Disconnecting all DGs every time a temporary fault occurs would make the system very unreliable. This is especially because most of the faults in overhead distribution systems are temporary. Thus, when the DG is not expected to be in islanding operation, a protection scheme that can keep DG on line to supply the load during the fault is necessary. The scheme should ensure that the OC PDs in on the feeder can clear the fault without loosing their proper coordination

The Impact of Synchronous Distributed Generation on Voltage Dip and Overcurrent Protection Coordination

This paper investigates the impact of synchronous Distributed Generation (DG) in MV network on coordination between overcurrent protection in MV feeder and voltage dip sensed by customer at LV side. DG is expected to support keeping the remaining voltage of a feeder high during voltage dip. DG location affects the level of support that DG can provide. Depending on the location, DG can either increase or decrease short circuit current. Both increasing and decreasing the short circuit current needs readjustment of overcurrent protection, either to ensure the coordination with downstream overcurrent protection, or to maximize DG support during the dip. A voltage dip immunity of a sensitive equipment (SE), which is shown in a voltage-time characteristic, is used to investigate the behaviour equipment during the dip