II Electric Power Industry in Indonesia

4. Measurement & Analysis of Supply Reliability

To ensure more accuracy in supply reliability analysis, measurement instruments were installed in each service coverage area. 6 instruments in total with 2 for each service area were installed and KEPCO staffs tried to install as many measurement instruments as possible at a wide variety of locations whenever they visited Indonesia.

In addition, the number of actual outages was confirmed to understand the level of supply reliability and voltage, power factor and other important electrical power quality metrics were secured from measurement data, which will be submitted in addition to the final report so that PLN branches may utilize for their distribution planning and operation in the future.

4-1 Detail of measurement

4-1-1 Semarang

As mentioned above 2 measuring devices are installed in each project site. Thus, in case of Semarang branch office these devices have been set up on the overhead transformers in Simpang Lima 4 feeder of Simpang Lima substation in the first measurement.

We have installed again these devices in another places after we have removed from the last place. In case of second measurement, Simpang Lima 1 feeder of Simpang Lima substation and Pandean Lamper 4 feeder of Pandean Lamper substation have been installed.

In case of third measurement, Sayung 5 and 6 feeder of Sayung substation have been installed. The detail of installation is shown in [Table 2-6].

We will dismantle those device and gather the data from devices on our 5th business trip.

[Table 2-6] Installation status of measuring device in Semarang

4-1-2 Surabaya

Same to Semarang branch office in case of south Surabaya branch office these devices have been set up on the overhead transformers in Ahmad Yani feeder and Bungurasih feeder of Waru substation in the first measurement. In case of second measurement, the overhead transformers of Ahmad Yani feeder in Waru substation have been installed. In case of third measurement, Kejaksaan feeder of Wonokromo substation and BLK1 feeder of Waru substation have been installed. The detail of installation is shown in [Table 2-7].

We will dismantle those device and gather the data from devices on our 5th business trip.

[Table 2-7] Installation status of measuring device in Surabaya

4-1-3 Denpasar

Same to Semarang branch office in case of South Bali branch office these devices have been set up on the overhead transformers in Sanur substation. In case of first and second measurement, the overhead transformers of Tanjung Sari and VIP feeder in Sanur substation have been installed. In case of third measurement, Bruan feeder and Sudirman feeder have been installed. The detail of installation is shown in [Table 2-8]. we will dismantle those device and gather the data from devices on our 5th business trip.

[Table 2-8] Installation status of measuring device in Bali

4-2 Analysis of Measured Data

In regard to the result of measurement from measuring device for reliability the accumulated data until now are not enough to analyse the reliability. We have finished only first time so we have a plan to install and uninstall more than twice in the future and gather more data. Through the gathered data we can find out the number of interruption, cause of interruption and duration of interruption in each project site during the measuring period. Furthermore, if possible we will compare the acquired data with daily report of interruption in each branch office and find out if record of interruption statistics is managed properly or not. The following shows the result of acquired data from measuring device which downloaded on our 3 times business trip.

4-2-1 Semarang

APJ Semarang suffers significant number of interruptions. During the 1st measurement, measurement was taken at 2 locations for about 3 months and interruptions occurred as often as eight times, which represented significantly more faults than expected, even considering the rainy season lasting from January through April. Therefore, it is necessary to analyze causes of faults accurately and develop countermeasures accordingly. During the 2nd and the 3rd measurement, interruptions occurred six times at the most or twice at the least in just 2 months, which represents a somewhat decreasing trend of fault occurrence during the seasonal transition to dry season, yet, indicates considerable number of faults. In annual terms, interruptions may occur 10 times or more at a single location. After all, customers connected to such lines suffer interruption at least once a month and the revenue of PLN from electricity sales may be impacted as significantly. Furthermore, damage to the corporate image arising in relation to inconvenience on the part of customers is also not to be ignored.

[Table 2-9] Result of acquired data from measuring device (Semarang)

4-2-2 Surabaya

Like APJ Semarang, interruptions occurred quite fruently in case of APJ Surabaya Selatan as well. During the 1st measurement, interruptions occurred as often as 3 times in just a month and, during the 2nd measurement, BH015 transformer was interrupted as frequently as six times. APJ Surabaya Selatan is analyzed to suffer 3 interruptions per line on monthly average, which is definitely not a good figure when seen from the perspective of supply reliability.

Therefore, just like APJ Semarang, APJ Surabaya Selatan must analyze causes of faults more thoroughly and develop countermeasures to prevent faults systematically in reference to the analysis. [Table 2-10] contains the measurement data analysis details for APJ Surabaya Selatan.

[Table 2-10] Result of acquired data from measuring device (Surabaya)

4-2-3 Bali

AJ Bali Selatan suffered fewer interruptions than other branches. During the 1st measurement, 2 interruptions occurred in 3 months and, during the 2nd measurement, interruptions increased a litte and began to fall at the beginning of seasonal transition to dry season. Although the number of faults was lower than other branches, AJ Bali Selatan suffers interruptions continuously in a short period of time lasting only a month or two. To bring supply reliability to a higher level, AJ Bali Selatan must also develop and enforce countermeasures to reduce faults more systematically.

[Table 2-11] Result of acquired data from measuring device (Bali)