?????? ?? ???? ??? ??? ???????? DC ? ?????? ?? ?? ???? ??? AC

1
(No Transcript)
2
?????? ?? ???? ??? ??? ???????? DC ? ?????? ?? ??
???? ??? AC
???? ??????? ??????? ????? ?????? ??? ??? 1388
3
DC ARC Furnace
4
?? ????? 1- ????? ???????? ???? ??? ??? DC 2-
??????? ???????? ???? ???? ??? ??? DC 3- ?????
??? ???????? ???? ??? ??? DC 4- ?????? ????? ???
???????? ???? ??? ??? AC ? DC 5- ?????? ?????
???? ???????? ???? ??? ??? AC ? DC 6- ??????
???? ????? ? ??????? ?? ???? ??? ??? AC ? DC 7-
?????? ????????? ? ??????? ???? ??? ??? AC ?
DC
5

• ?????? ???? DC ???? ?? AC
• - ??????? ???? ??? ???????? ?? ????? DC
• - ???? ???? ???????
• - ???? ???? ?????
• - ???? ???? ??? ? ????? ?? ??????
• - ???? ????? ?? ????? ???? ???? ??????
• - ????? ???? ?? ??? ?? ?? ??? ??????? ? ???? ???
• - ???? ????? ????? ? ??????? ?? ???? ?????
  ???????? ??????? ????
• - ?????? ????

6
(No Transcript)
7
(No Transcript)
8
????? ???????? ???? AC
9
(No Transcript)
10
????? ???????? ???? DC
11
(No Transcript)
12
?????? ?.?.?. ?? ????? ??????

13
(No Transcript)
14
????? ??? ?? ???? ??? ??? DC
15
????? ????? ?? ???? AC ? DC
16
?????? ???? ????? 12 ?????
17
?????? ???? ????? 24 ?????
18
???????????? ??????? ? ???? ????? ??? ???? ??? DC
19
????? ???? ??? DC
20
???? ????? ???? ??? DC
21
Power-voltage curves for DC arc furnace
22
?????? ???? ??? DC ? AC

• - ???? ????? 5 ?? 7
  ???? ????
• - ???? ??????? 50 ????
  ????
• - ????? ? ??? ????????
• - ???? ???? 20
  ???? ????
• - ?????
  80 ???? ????
• - ????? ??????? ?? ????
• - ?? ??? ??????? ?? ????
• - ????? ???? DRI ?????
• - ????? ? ??????? ????
• - ?????? ? ???? ????
• - ????? ????

23
(No Transcript)
24
????? ????? ???? ?? ???? DC
25
??? ???????? ??? ??? AC
26
?? ???? ????????? IEC
27
(No Transcript)
28
(No Transcript)
29
(No Transcript)
30
(No Transcript)
31
????? ????? ???? ???? DC
32
(No Transcript)
33
(No Transcript)
34
????? ???? DC
35
??? ?????? ??? DC ??? ?????
36
??????? ???? ?????? ?? ????? ? ???? ?????
37
???? ??? ?? ?? ???????
38
(No Transcript)
39
(No Transcript)
40
?????? ???? ??? ?? ?? ???????
41
?????? ???? ??? ?? ?? ???????
42
?????? ???? ??? ?? ?? ???????
43
?????? ???? ??? ?? ?? ???????
44
Advantage Of D.C. Arc Furnace Over A.C. Arc Furnace 

DC mode of operation ensures high arc stability, eliminates inrush currents and disturbances in Power System.  Reduces electrode consumption by 60. Lower energy consumption by 5 - 7. Absence of Hot Spots and Lower refractory consumption by 20. DC flicker is 20 of AC flickers as current control reduces fluctuation of reactive power, Can also work on weak lines. Homogeneous temperature composition due to intense stirring in molten metal. Ability to melt high percentage of DRI in the charge. Fewer mechanical components with less wear tear reduce maintenance costs to only 40. Environment friendly system with lower dust load by 80 hence lower cost of pollution control equipment UNIARC does not require Static VA Compensators for operation.   
?????? ???? ??? ??? DC ???? ?? AC
45
?????? ??????? ???? DC ? AC
46
????????? ???? ??? ???? ??? ??? ????????

47
??????? ??? ???? DC ?? ??? ???
48
?????? ????? ???????? ??? ????? ?? ?? ???? ??? DC
49
Load and Supply Characteristics

• DC Arc Furnace
• Contract demand of 100 MW
• 345 kV PCC, 7811 MVA SC
• SVC on 34.5 kV Bus
• 2nd, 3rd, 5th, 7th, 12th (HP) filters

50
Load Current Statistics
51
Load Current Waveforms
Light Load
Heavy Load
52
Arc Furnace Generated Waveform Distortion

• Difficult to classify and separate phenomena
• Attributes of both transient and steady state
  phenomena
• Waveform distortion characteristics change
  rapidly
• Observed interharmonic levels may be due to
  actual interharmonic injection, a side effect due
  to the changing load, or both
• Use appropriate analysis method based on expected
  impact to system
• Harmonic, Interharmonic, Transient, Flicker,
  Unbalance

53
Interharmonic Impacts

• Makes filter design more difficult
• Adverse impact on control systems
• Can excite low frequency oscillations in
  mechanical systems
• Communications interference
• Light flicker

54
12 Cycle Snapshot
55
Spectrum of Snapshot
56
Results for Currents
57
More Current Results
58
Results for Voltages
59
More Voltage Data
60
More Voltage Data
61
Conclusions

• IEC measurement methods are relatively easy to
  apply - similar level of effort as for harmonic
  measurements
• Measured levels are low
• Difficult to measure accurately (A/D resolution)
• Statistical techniques required (many samples)
• Low levels can cause observable impacts
• More work on relating impacts to measured levels
  required

62
?? ???? ? ???????