IND UCTIVE COORDINA TION 



97 



Assume, however, that instead of supplying the single-phase loads in 

 the area shown on Fig. 3 from one phase only, the single-phase loads 

 were distributed reasonably uniformly among the phases. This would 

 be advantageous not only by the noise reduction possibilities, which 

 will be more fully discussed but also by the improved regulation 

 attainable on the feeder. Figure 4 shows a possible rearrangement of 

 Fig. 3 along these lines and Table III shows the noise conditions with 

 the feeder arrangements of Fig. 4. 



TABLE III 



Noise Contributions (Fig. 4) of Various Harmonics and Sections 



OF Exposure 



* Location C — For party-line service using 8A ringers, during heavy power loads. 



A comparison of Tables I and III shows that the noise from the non- 

 triple harmonics has been very materially reduced by the balancing of 

 loads made possible by the more favorable feeder arrangement of Fig. 



TABLE IV 



Comparison of Effectiveness of Various Remedial Measures 



(Fig. 4) 



Approximate Noise on Party-Line Stations 

 (Heavy Power Loads) 



Type of Remedial Measure Location A or B Location C 



1. Before applying remedial meas- 



ures 480 noise units 735 noise units 



2. Using special telephone station 



sets 25-30 " " 40-50 " 



3. Avoiding exposure in section a-5 



by cooperative planning of 



routes. 190 " " 460 " 



4. Interconnecting 300 kva wye- 



delta bank with system neutral 330 " " 535 " " (26 kv. 



of unbal- 

 anced load) 



5. Cable sheath shielding — ground- 



ing at jet. pole and to 1 ohm 



ground at X 325 " " 420 " 



6. Combinations of measure 3, 4, 



and 5 85 " " 245 " 



