Distribution Substation Transformer Research Articles

Evaluation of Distribution Transformer Placement Optimal Based on Load Balance

The distribution system is divided into primary and secondary distribution networks. The primary distribution network is the network from the main substation transformer (GI) to the distribution substation, while the secondary is the channel network from the distribution substation transformer to the consumer or load. The primary distribution network is better known as the medium voltage network (JTM 20kV) while the secondary distribution is the low voltage network (JTR 220/380V). The distribution network is the part of the electric power system that is closest to customers or loads compared to the transmission network. Currently, network electricity conditions throughout Indonesia are experiencing a decline of 5% which is due to various factors such as the medium-scale diameter of the conductors used, so at the farthest SR the value of overvoltage is 10%, the allowable voltage drop and must anticipate an increase in electrical load of 22.7 %, the placement of the transformer is not optimal and the distance the electrical energy travels from the transformer to the load is not paid enough attention so that the capacity of a transformer is not optimal and the voltage drop is also greater. Given these conditions, re-evaluation and planning is needed that takes into account planning criteria such as allowable voltage drops and continuity of electricity services so that optimization of the network used can emerge.

Procuring flexibility in power systems with incentive-based grid access requests

Demand-side flexibility is an important tool for enhancing the interaction of renewable energy resources and reducing the need for grid upgrades. To employ this flexibility as a market product, it is necessary to aggregate and coordinate by coordinating responsive loads. In this regard, designing effective load coordination mechanisms that consider the preferences of aggregators, end-users, and network operators is critical for the successful implementation of demand response (DR) programs. This paper proposes an incentive-based method for coordinating a group of controllable devices that is practical, does not require complex, high-order models of the entire system, respects end-users privacy and quality of service (QoS), and can readily incorporate network conditions to ensure grid reliability. The proposed method includes algorithms at both the end-user level for controllable device operation and the aggregator level for managing the grid access requests. These algorithms are fast and with low computational burden which makes them suitable for the designed framework, reduces the implementation cost and increases the chance of scalability. The method is illustrated with a realistic test system consisting of a set of controllable heat pumps used in pool heating systems and uncontrollable loads placed in a distribution feeder and supplied by a distribution substation transformer. Simulation results highlight the effectiveness of the proposed method in satisfying the controllable device, end-users, and grid constraints. Comparing the results with similar existing methods shows that the method is 11% more cost-effective than traditional ON/OFF methods while reducing the number of rejected grid access requests from the devices, significantly.

ANALISIS DAMPAK OVERLOAD TRANSFORMATOR TERHADAP KUALITAS DAYA GARDU K622 PENYULANG PELANGI PT. PLN ( PERSERO ) ULP KARANG

Transformer overload occurs in one of the distribution transformers in PT. PLN (Persero) ULP Karang,namely the K622 Distribution Transformer at the Rainbow Feeder with a load of 110.16% exceeding the standard set by SPLN, which is 80%. This study aims to find out how to overcome the Overload problem in the K622 distribution substation transformer on The Rainbow and get the size of the K622 distribution substation transformer load before and after the Uprating Transformer. From the results of uprating, the percentage of transformer loading value before uprating transformers was carried out by 110.16% and after uprating transformers by 26.38% so that it decreased by 83.78%. This means that the uprating transformer is one of the methods that can be used to overcome excess loads.

Distribution Substation Transformers: Understanding North American Standards Defining Transformer Performance, Testing, Installation, and Maintenance

Distribution Substation Transformers: Understanding North American Standards Defining Transformer Performance, Testing, Installation, and Maintenance

Fuzzy mamdani logic inference model in the loading of distribution substation transformer SCADA system

<span id="docs-internal-guid-152e332e-7fff-7073-a541-1d420decb47b"><span>The research objective of supervisory control and data acquisition (SCADA), with fuzzy Mamdani logic simulation on the loading section of distribution transformer substations. Data acquisition is available when saving SAIFI SAIDI data and storing the results of monitoring equipment. The method used is Mamdani fuzzy logic, there are two input variables, namely current and voltage devices. The membership function in Mamdani fuzzy logic has been created based on the input current and voltage variables. Currently: parameter {0, 600} low is created {0, 350, 450, 600}, normal {400-650} parameter is created {400, 500, 550, 650}, parameter high {≥600} is created {600, 650, 750, 1000}, when determining the voltage: low {≤10.5} parameters {0 4 7 10.5}, normal {9-14} parameters {9, 10, 13, 14} and high {≥13} - parameters {13, 14, 15, 16}. Based on the results of the Mamdani logic rule test on the output current containing a transformer and a voltage sensor, the results obtained are IF (normal current; (630) AND voltage (high); (13.2) (high load transformer). The components in the simulation tool include miniature substations made with the 1A travel substation model, 3A substation as the main substation, the relay as distribution substation as the monitoring application. Telestatus and Telecontrol use a microcontroller. Initial scenario. After substation is resumed, data is stored after downtime, service life, duration, and data period. Initial scenario After substation is resumed, data is stored after downtime, service life, duration, and data period.</span></span>

On the role of prosumers owning rooftop solar photovoltaic in reducing the impact on transformer’s aging due to plug-in electric vehicles charging

This paper investigates the synergetic effect of rooftop solar photovoltaic (PV) generation owned by residential prosumers (power producers and consumers) on reducing the distribution substation transformer’s aging caused by charging plug-in electric vehicles (PEVs). Unlike previous work considering surveys based on internal combustion engine-based vehicle data (e.g., National Household Travel Survey (NHTS)) are used in estimating the charging demand of PEVs, this work considers actual PEVs charging data based on the 2015 Canadian Plug-in Electric Vehicle Survey (CPEVS). This work further quantifies the resultant aging seen on substation transformers when internal combustion engine-based National Household Travel Survey data as compared to plug-in electric vehicle driving data from the Canadian Plug-in Electric Vehicle Survey. Moreover, a comparison of the substation transformer aging is performed based on varying plug-in electric vehicle charging levels. Results of the scenarios have shown substation transformer loss of life is found to be at least 30% higher when vehicle data is based on plug-in electric vehicle studies versus conventional internal combustion engine vehicles with 0% PV penetration, up to twice as high at 100% PV penetration. Further studies have shown grouped plug-in electric vehicle charging using 3.3kW at 7pm results in twice the transformer aging seen versus plug-in electric vehicles charging beginning upon returning home. Finally, results have shown that the effect of rooftop solar PV owned by residential prosumers was found to reduce substation transformer loss-of-life by 75% in the case of 3.3kW plug-in electric vehicle charging when 100% PV penetration was added to the system. Such reduction is due to a decrease in transformer’s winding hot-spot temperature caused by PV generation despite the non-coincidence between the peak charging demand of plug-in electric vehicles and the peak power generation from rooftop solar photovoltaic.

Harmonics Impact a Rising Due to Loading and Solution ETAP using the Distribution Substation Transformer 160 kVA at Education and Training Unit in PT PLN

Harmonics is a result of the progress of the use of non-linear loads are used in homes and offices. On the other hand, the energy crisis triggered the increased use of Energy Saving Lamps (LHE), Computer, electronic power equipment that is the cause of harmonics that can interfere with the electrical distribution system including Distribution Transformer (TGD). By performing measurements in the TGD, it is known the existence of harmonic currents which can increase the losses on the TGD. In the measurements made on the TGD Education and Training Unit Lubuk Alung capacity of 160 kVA obtained that influence THDi (Total Harmonic Distortion) currents in the TGD (6.57%) while according to the standard (4%). Shrinkage of 1.22 years of age transformer (4.067%). By using ETAP simulation active capacitor installation of 60 KVAR and 1500 mH obtained THD decline to 8% by neutral currents down to 12 A. From the simulation results ETAP effective current of each phase down 6% while the neutral current down 64%. Transformer derating of these conditions can be avoided and the use of the load can be increased. The impact of harmonics on transformer resulting in transformer losses increased from 3,755 kW to 3.775 kW. The increase in transformer losses (0.16 %) led to decreased work efficiency transformer. This resulted in a decrease in the capacity of the transformer.

General and Simple Decision Method for DG Penetration Level in View of Voltage Regulation at Distribution Substation Transformers

A distribution system was designed and operated by considering unidirectional power flow from a utility source to end-use loads. The large penetrations of distributed generation (DG) into the existing distribution system causes a variety of technical problems, such as frequent tap changing problems of the on-load tap changer (OLTC) transformer, local voltage rise, protection coordination, exceeding short-circuit capacity, and harmonic distortion. In view of voltage regulation, the intermittent fluctuation of the DG output power results in frequent tap changing operations of the OLTC transformer. Thus, many utilities limit the penetration level of DG and are eager to find the reasonable penetration limits of DG in the distribution system. To overcome this technical problem, utilities have developed a new voltage regulation method in the distribution system with a large DG penetration level. In this paper, the impact of DG on the OLTC operations controlled by the line drop compensation (LDC) method is analyzed. In addition, a generalized determination methodology for the DG penetration limits in a distribution substation transformer is proposed. The proposed DG penetration limits could be adopted for a simplified interconnection process in DG interconnection guidelines.

Power system single step restoration incorporating cold load pickup aided by distributed generation

When a system is restored after an extended outage, the demand is greater than that was before the outage. The increase in the demand is due to the cold load pickup (CLPU) condition. The attempt to restore such load simultaneously will cause an excessive loading on the network elements in addition to limits violation. For these reasons, step-by-step restoration was suggested by researchers to overcome such problem. However, this way of restoration requires a long time for the complete system to be back to service. In this paper, simultaneous single step restoration of transmission and distribution networks is introduced with the help of distributed generation (DG) units optimally sited and sized by particle swarm optimization (PSO) algorithm. The aim of the proposed DG allocation algorithm is to reduce the distribution substation transformer loss of life due to overloading and to reduce the lost load and hence the additional power demand caused by CLPU. The capacity of the DG required is determined on the basis of additional power demand and the load diversity preserved. The proposed algorithm is applied to the Egyptian 66 kV transmission network in the city of Alexandria including a 33-bus and a 69-bus, 11 kV primary distribution feeders.

A value-based probabilistic approach to designing urban distribution systems

Achieving high distribution reliability levels and concurrently minimizing capital costs can be viewed as a problem of optimization. Assuming given outage rates and repair times, distribution system design is the remaining factor in determining customer reliability. Including customer value of reliability in an economic analysis allows for optimization of the major components of distribution system design. Using mathematical models and simulations, a comparison of design concepts can be performed to compute the optimal feeder section length, feeder loading level, and distribution substation transformer loading level. The number of feeder ties and feeder tie placement are also optimized through the models. The overall outcome of this analysis is that capital costs can then be directed towards system improvements that will be most cost-effective in improving system reliability. This paper presents a value-based probabilistic approach to designing urban distribution systems. The value-based reliability methodology is illustrated using a practical urban distribution system of MidAmerican Energy Company.

Determining number and timing of substation spare transformers using a probabilistic cost analysis approach

Compared to the N-1 security design principle in each substation, common spare transformers shared by multiple substations can avoid considerable capital expenditure and still assure a sufficient reliability level. Using common spare transformers has been already a practice of some electric utilities in distribution substation transformer planning. This paper presents a probabilistic approach to determining the number and timing of spare transformers shared in a substation group. The proposed approach is based on the aging failure model of transformers, the overall reliability analysis and the probabilistic damage cost model for a substation group, the capital cost model for spares and the present value method. The spare transformer scheme obtained using the presented approach provides both cost efficiency and sufficient reliability. A single transformer substation group in a nonurban region is given as an application example to illustrate the procedure of the method.

Distribution system design optimization for cold load pickup

This paper presents a study on the optimal design of power distribution systems. Distribution substation transformer size and feeder sectionalizing switches are selected such that a cold load pickup situation can be handled while minimizing an annual cost function. The cases of a distribution substation with one or more transformer(s) are considered. In the latter case, the optimisation problem is formulated based on the worst-case scenario of having one of the transformers out of service.

Effects of Cold Load Pickup at the Distribution Substation Transformer

The cold load pickup characteristics of electric space heating loads and its effect on the distribution substation transformer and its protective equipment is presented. A computer simulation Qf cold load pickup characteristics as seen at the substation level is used to determine the impact of saturation of electric space heat load on the various thermal and loading limitations of transformers.

Effects of Cold Load Pickup at the Distribution Substation Transformer

Effects of Cold Load Pickup at the Distribution Substation Transformer

A New Method of Generating Twacs?? Type Outbound Signal for Communication on Power Distribution Networks

This paper describes a new method of generating TWACS®type outbound signals. The signal is generated by drawing a smal l control led current through the distribution substation transformer winding. The voltage drop across the transformer leakage inductance is the modulation voltage. Propagation characteristics, interwinding coupling in 3 phase transformers, detection. method and field data are discussed and presented in this paper.

A New Method of Generating TWACS®Type Outbound Signals for Communication on Power Distribution Networks

This paper describes a new method of generating TWACS®type outbound signals. The signal is generated by drawing a smal l control led current through the distribution substation transformer winding. The voltage drop across the transformer leakage inductance is the modulation voltage. Propagation characteristics, interwinding coupling in 3 phase transformers, detection. method and field data are discussed and presented in this paper.

A Distribution Substation Rating Strategy Based Upon Reliability Analysis

The reliability of service based upon the single contingency failure of a distribution substation transformer has been quantified. Algorithms for the calculation of the expectation value of having load out of service for this contingency have been developed. This probability is based upon the annual load distribution curve of the distribution substation and for various levels of tie capacity available for diverting load. The effects of distribution automation for the reconfiguration of large areas of a distribution system can be evaluated with these models.

Active acoustic absorbers for low-frequency hum

Previous attempts to cancel the 120-Hz hum of large power transformers by active means have relied only upon Young's principle [e.g., W. B. Conover, Noise Control 2, 78–82 (1956)]. M. Jessel established that Young's principle of interference can be combined with Huygens' principle of virtual sources [Brevet Français 1, 494–967 (1966)]. This new theory suggested a technique by which the sound field may be cancelled completely outside of a Huygens' surface surrounding a primary source, by employing a number of secondary sources at the Huygens' surface, which act as active sound absorbers. The theory has been realized experimentally for sound in a duct [M. Jessel and G. Mangiante, J. Sound Vib. 23, 383–390 (1972)] and in three dimensions for a small simple source [G. Mangiante, D.E.S. Fac. Sciences, Marseilles (1968)]. This technique has been applied by the authors to a small acoustic model of a large distribution substation transformer in a free-field over a reflecting plane. Six-ten dB attenuation of the fundamental frequency has been achieved everywhere in the farfield using only a limited number of secondary sources. Cancellation of two hum components simultaneously has been achieved also. It also has been found that attenuation over a limited horizontal angle does not increase the radiation outside this angle significantly.