Current Carrying Capacity Of Overhead Transmission Line Acsr Conductor 623y36
This document was ed by and they confirmed that they have the permission to share it. If you are author or own the copyright of this book, please report to us by using this report form. Report 3i3n4
Overview 26281t
& View Current Carrying Capacity Of Overhead Transmission Line Acsr Conductor as PDF for free.
More details 6y5l6z
- Words: 1,902
- Pages: 8
Current Carrying Capacity of Overhead Transmission Line ACSR Conductor. 21.1 INTRODUCTION 21.1.1 The thermal capabilities of transmission transmission lines in Power System are evaluated based on the criteria of maximum operating or design temperatures of the transmission line conductors and the transmission losses. 21.1.2 The thermal rating of conductor is dependent on the following factors : A. Meteorological/Environmental Conditions 1. Solar radiation. 2. Wind velocity. 3. Ambient temperature. B. Conductor surface Characteristics 1. Age of the Conductor. 2. Maximum design conductor temperature. 3. Allowable losses of strength of aluminium metal at design temperature. 21.1.3 The maximum value of temperature at which transmission metal at design temperature. Operate in India is 650 C for conductors as per provisions of IS:802 (Part-I) 1973. However, to increases loading capabilities of transmission lines, the matter is under active consideration by Bureau of Indian Standards, Central Electy. authority, State Electy Boards and other utilities etc. for increasing the maximum conductor design temperature from 650 C to 750 C as it has been observed that there is no loss of strength of aluminium metal at 650 C. But it has to be ensured that the transmission line towers are designed suitably, fo that there is no violation of ground clearance under any circumstances due to safety considerations. This would significantly help in improving thermal loading capability of transmission lines, without infringement in ground clearances. 21.2 HEAT BALANCE EQUATION OF ELECTRICAL CONDUCTORS The current carrying capacity rating is computed by using the following formula under steady state condition of wind velocity, temperature, solar radiation and electric current. Qc + Qr = I2 R + Qs WhereI2 R = Heat generated in the conductor due to flow of current ' I ' in Amperes, R is the resistance of the conductor per meter. Q8 = Solar Heat Gain in Watts per meter of Conductor. Qc = Convection heat loss in Watts per meter of Conductor Qr = Radiated Heat Loss in Watts per meter of Conductor. From the above equation, current carrying capacity I can be determined asI = √ Qc + Qr - Qs / R Ampere The effect of Heat Gain due to Magnetic Heat and Corona Heating and Heat Loss due to Evaporation is usually negligible, hence not considered. 21.3 CURRENT RATING OF VARIOUS CONDUCTORS 21.3.1 The size of the conductor used for transmission lines of various voltage class has now been standardized, which are as fallows400kv - 'Moose' ACSR 220kv - 'Zebra' ACSR 132kv - 'Panther' ACSR 21.3.2 However, recently in some cases 'moose' conductor has been used on 220kv lines for evacuation of bulk power from generating station, such as Unchahar Power Project, In case of 66kv lines which have been up-graded to 132kv, the conductor used is 'Dog' ACSR. Accordingly, the current capacities of the above conductors are temperature of 47.50 C. for new as well as old conductors for the designed maximum conductor temperature of 650 C as well as 750 C. TABLE 21-II
Sl. No.
Size of Conductor (Code Name)
Current carrying Capacity in Amperes At maxim. designed Temperature of 650 C
At maxim. designed temperature of 750 C
New Conductor (Up to one year)
Old Conductor (Beyond 10 years)
New Conductor (Up to one year)
Old Conductor (Beyond 10 years)
1.
'Dog' ACSR
141.12
150.20
229.65
245.06
2.
'Panther' ACSR
179.89
200.60
340.83
371.42
3.
'Zebra' ACSR
201.26
249.51
496.46
553.70
4.
'Moose' ACSR
133.60
218.89
530.51
603.78
NOTE :
1. It is observed that the temperature at some place of UP State goes as high 47.50 C during the months of April, May & June. There fore current carrying capacities of conductors indicated above, are for worst condition of ambient temperature. However, the current carrying capacity of the conductor of the increases as the ambient temperature decreases. 2. The current carrying capacity of the conductor also increases with the age of the conductor as would be observed from the above tabel. 21.4 POWER TRANSMITTED 21.4.1 The power transmitted for any size of conductor depends on its current carrying capacity and can be calculated from the following formulaPower in KW = √ 3 V I Cos Ф Power in KW = √ 3 V I Cos Ф / 1000 WhereCos Ф = Power Factor (P.F.) V = Voltage in KV I = Current in Amp. Assuming Power Factor of 0.8 lagging, power transmitted at various voltages can be calculated approximately as follows-
a. At 132 kv
b.
Power in MW = √ 3 132 x I x 0.8 / 1000 = 0.1828992 x I = 0.183 x I At 220 kv Power in MW = √ 3 220 x I x 0.8 / 1000 = 0.305 x I
c. At 400 kv Power in MW = √ 3 400 x I x 0.8 / 1000 = 0.554 x I
Thus value of power transmitted can easily be calculated at 132 kv or 200 kv or 400 kv for a given value of current. 21.4.2 Normally for continuous operation the transmission lines used on various voltage are designed to carry or transmit maximum power loads at the designed maximum conductor temperature of 650 C as follows At 132 kv with 'Panther' ACSR = 75 MVA At 220 kv with 'Zebra' ACSR = 200 MVA At 400 kv with 'Moose' ACST = 500 MVA 21.4.3 It is worth considering that the maximum permissible conductor temperature for continuous operation on transmission lines may be introduced as 750 C in order to raise the current rating of the conductor. This issue is under active consideration and IS:802-1973 is under revision. 21.4.4 It is observed that the current carrying capacity of any conductor at any particular temperature is lowest during 10 to 14 hours of a day. Assuming maximum permissible conductor temperature of 750 C, the value of current carrying capacities of 'Dog', 'Panther', 'Zebra' and 'Moose' ACSR conductor during 10 to 14 hours of a day at different ambient temperatures for various months of a year for the conductor of ages (a) up to one year (b) between 1 to 10 years and (c) Above 10 years given in the Table I, II, III & IV respectively hereinafter.
Table 21-II 21.5 Continuous Current Carrying Capacity of ACSR Conductors
1. 2. 3. 4. 5.
Code Name & Size Overall diameter Resistance at 200 C Maximum Design Temp. of conductor Region
Month
January
February
March
April
May
June
July
August
Ambient Temperature in °C
ACSR 'Dog' 14.15mm 0.2792 ohns/Km 750 C Northern
Continuous current carrying capacity in Amp during 10 to 14 HRS for conductor of age Up to one year
Between one to Ten years
Beyond 10 years
47.5
252.46
263.43
269.12
45.0
268.06
279.70
285.48
40.0
296.87
309.67
315.64
32.5
335.18
349.38
355.60
20.0
390.01
405.95
412.51
47.5
244.49
254.83
260.71
45.0
260.56
271.61
277.57
40.0
290.12
302.39
308.50
32.5
329.21
342.94
349.28
20.0
384.89
400.42
407.07
47.5
237.01
246.76
252.82
45.0
253.56
264.05
270.17
40.0
283.85
295.62
301.86
32.5
323.70
336.99
343.43
20.0
380.19
395.33
402.07
47.5
230.37
239.58
245.82
45.0
247.36
257.36
263.63
40.0
278.33
289.65
296.02
32,5
318.87
331.77
338.31
20.0
376.09
390.89
397.70
47.5
231.59
240.89
247.10
45.0
248.50
258.58
364.83
40.0
279.33
290.74
297.09
32.5
319.75
332.72
339.24
20.0
376.83
391.69
398.49
47.5
229.65
238.80
245.06
45.0
266.74
256.63
262.93
40.0
277.73
289.01
295.39
32.5
488.42
513.25
525.82
20.0
581.71
609.99
622.97
47.5
341.41
359.68
372.02
45.0
370.17
389.85
402.94
40.0
421.94
443.98
556.32
32.5
488.82
513.68
526.24
20.0
582.05
610.35
623.32
47.5
342.99
361.37
373.65
45.0
370.63
391.40
403.65
40.0
423.22
445.35
457.66
Table 21-IV 21.7 Continuous Current Carrying Capacity of ACSR Conductors 1. 2. 3. 4. 5.
Code Name & Size Overall Diameter Resistance at 200 C Maximum Design Temp. of conductor Region
Month
January
February
March
April
May
June
July
Ambient Temperature in "C
ACSR 'Zebra' 28.62mm 0.06888 ohns/Km 750 C Northern
Continuous current carrying capacity in Amp during 10 to 14 HRS for conductor of age Up to one year
Between one to Ten years
Beyond 10 years
47.5
580.38
619.16
638.95
45.0
621.77
662.58
682.56
40.0
697.27
714.63
762.03
32.5
796.22
844.93
865.99
20.0
935.83
989.97
1012.02
47.5
551.61
588.83
609.60
45.0
595.01
734.33
655.17
40.0
673.52
716.50
737.59
32.5
775.50
822.96
844.57
20.0
918.26
971.29
993.76
47.5
524.11
559.85
581.67
45.0
569.61
607.53
629.26
40.0
651.18
692.89
714.68
32.5
756.19
802.48
824.63
20.0
902.01
954.00
976.87
47.5
499.18
533.61
556.45
45.0
546.75
583.44
606.03
40.0
631.29
671.86
694.31
32.5
739.13
784.40
807.05
20.0
887.76
938.84
962.07
47.5
503.78
538.45
561.09
45.0
550.96
587.87
610.29
40.0
634.94
675.71
698.04
32.5
742.24
787.70
810.25
20.0
890.35
941.60
964.76
47.5
496.46
530.74
553.70
45.0
544.27
580.81
603.50
40.0
629.14
669.58
692.11
32.5
737.29
782.45
805.15
20.0
886.23
973.21
960.48
47.5
497.55
531.89
554.80
August
September
October
November
December
45.0
545.26
581.86
604.51
40.0
630.00
670.49
692.99
32.5
738.02
783.23
805.91
20.0
886.84
937.86
961.11
47.5
500.54
535.04
559.82
45.0
547.99
584.74
607.28
40.0
632.27
672.99
695.41
32.5
740.04
785.27
807.99
20.0
888.52
939.65
962.86
47.5
528.75
564.74
586.37
45.0
573.88
612.04
633.61
40.0
654.92
696.84
718.51
32.5
759.41
805.90
827.96
20.0
904.71
956.88
979.68
47.5
543.19
579.94
601.03
45.0
587.20
626.10
647.20
40.0
666.63
709.22
730.52
32.5
769.53
816.63
828.40
20.0
913.23
965.93
988.52
47.5
56.66
604.69
624.94
45.4
608.98
649.08
669.46
40.0
685.89
729.59
750.32
32.5
786.28
834.38
855.71
20.0
927.38
980.98
1003.24
47.5
583.42
622.35
642.05
45.0
624.60
665.57
685.46
40.0
699.80
744.30
764.63
32.5
798.44
847.27
868.28
20.0
937.71
991.97
1013.98
Table 21-V 21.8 Continuous Current Carrying Capacity of ACSR Conductors 1. 2. 3. 4. 5.
Code Name & Size Overall Diameter Resistance at 200 C Maximum Design Temp. of conductor Region
ACSR 'Moose' 31.77mm 0.05595 ohms/Km 750 C Northern
Month
January
February
March
April
May
June
July
August
September
Ambient Temperature in °C
Continuous current carrying capacity in Amp during 10 to 14 HRS for conductor of age Up to one year
Between one to Ten years
Beyond 10 years
47.5
637.49
686.07
710.72
45.0
685.66
736.61
761.41
40.0
773.28
828.37
853.58
32.5
887.67
947.87
973.80
20.0
1048.65
1115.27
1142.39
47.5
601.14
648.10
674.14
45.0
652.00
701.39
727.39
40.0
743.59
797.21
823.37
32.5
862.93
920.77
947.44
20.0
1062.96
1092.32
1119.92
47.5
566.09
611.58
639.10
45.0
619.84
667.78
695.04
40.0
715.56
767.80
794.94
32.5
837.87
895.43
922.84
20.0
1006.84
1071.05
1099.18
47.5
534.03
578.23
607.27
45.0
590.70
637.38
665.88
40.0
690.48
741.51
769.58
32.5
816.55
872.91
901.08
20.0
989.17
1052.77
1080.98
47.5
539.97
584.40
713.15
45.0
596.08
642.98
671.25
40.0
695.08
746.34
774.22
32.5
820.45
877.09
905.05
20.5
992.39
1055.77
1084.29
47.5
530.51
574.56
603.78
45.0
587.52
634.06
662.70
40.0
687.75
738.66
766.83
32.5
814.25
87057
898.73
20.0
987.28
1050.36
1079.02
47.5
531.92
576.03
605.18
45.0
588.79
635.39
663.98
40.0
688.84
739.80
676.93
32.5
815.17
871.54
899.67
20.0
988.04
1051.16
1079.81
47.5
535.79
580.05
609.00
45.0
592.29
639.03
667.46
40.0
691.83
742.92
770.95
32.5
817.70
874.20
902.25
20.0
990.12
1053.37
1081.96
47.5
572.01
617.76
645.02
October
November
December
45.0
645.26
673.44
700.42
40.0
720.27
722.74
799.70
32.5
841.89
899.68
926.94
20.0
1010.19
1074.59
1102.63
47.5
590.43
636.93
663.41
45.0
642.14
691.08
717.45
40.0
734.96
788.15
814.61
32.5
854.50
912.94
939.83
20.0
1020.72
1085.73
1113.49
47.5
620.18
667.99
693.28
45.0
669.40
719.80
745.16
40.0
759.07
813.45
839.11
32.5
875.32
934.87
961.15
20.0
1038.22
1104.24
1131.54
57.5
641.30
690.06
714.57
45.0
689.21
740.33
765.01
40.0
776.42
831.67
856.79
32.5
890.41
950.76
976.62
20.0
1050.97
1117.72
1144.71
Sl. No.
Size of Conductor (Code Name)
Current carrying Capacity in Amperes At maxim. designed Temperature of 650 C
At maxim. designed temperature of 750 C
New Conductor (Up to one year)
Old Conductor (Beyond 10 years)
New Conductor (Up to one year)
Old Conductor (Beyond 10 years)
1.
'Dog' ACSR
141.12
150.20
229.65
245.06
2.
'Panther' ACSR
179.89
200.60
340.83
371.42
3.
'Zebra' ACSR
201.26
249.51
496.46
553.70
4.
'Moose' ACSR
133.60
218.89
530.51
603.78
NOTE :
1. It is observed that the temperature at some place of UP State goes as high 47.50 C during the months of April, May & June. There fore current carrying capacities of conductors indicated above, are for worst condition of ambient temperature. However, the current carrying capacity of the conductor of the increases as the ambient temperature decreases. 2. The current carrying capacity of the conductor also increases with the age of the conductor as would be observed from the above tabel. 21.4 POWER TRANSMITTED 21.4.1 The power transmitted for any size of conductor depends on its current carrying capacity and can be calculated from the following formulaPower in KW = √ 3 V I Cos Ф Power in KW = √ 3 V I Cos Ф / 1000 WhereCos Ф = Power Factor (P.F.) V = Voltage in KV I = Current in Amp. Assuming Power Factor of 0.8 lagging, power transmitted at various voltages can be calculated approximately as follows-
a. At 132 kv
b.
Power in MW = √ 3 132 x I x 0.8 / 1000 = 0.1828992 x I = 0.183 x I At 220 kv Power in MW = √ 3 220 x I x 0.8 / 1000 = 0.305 x I
c. At 400 kv Power in MW = √ 3 400 x I x 0.8 / 1000 = 0.554 x I
Thus value of power transmitted can easily be calculated at 132 kv or 200 kv or 400 kv for a given value of current. 21.4.2 Normally for continuous operation the transmission lines used on various voltage are designed to carry or transmit maximum power loads at the designed maximum conductor temperature of 650 C as follows At 132 kv with 'Panther' ACSR = 75 MVA At 220 kv with 'Zebra' ACSR = 200 MVA At 400 kv with 'Moose' ACST = 500 MVA 21.4.3 It is worth considering that the maximum permissible conductor temperature for continuous operation on transmission lines may be introduced as 750 C in order to raise the current rating of the conductor. This issue is under active consideration and IS:802-1973 is under revision. 21.4.4 It is observed that the current carrying capacity of any conductor at any particular temperature is lowest during 10 to 14 hours of a day. Assuming maximum permissible conductor temperature of 750 C, the value of current carrying capacities of 'Dog', 'Panther', 'Zebra' and 'Moose' ACSR conductor during 10 to 14 hours of a day at different ambient temperatures for various months of a year for the conductor of ages (a) up to one year (b) between 1 to 10 years and (c) Above 10 years given in the Table I, II, III & IV respectively hereinafter.
Table 21-II 21.5 Continuous Current Carrying Capacity of ACSR Conductors
1. 2. 3. 4. 5.
Code Name & Size Overall diameter Resistance at 200 C Maximum Design Temp. of conductor Region
Month
January
February
March
April
May
June
July
August
Ambient Temperature in °C
ACSR 'Dog' 14.15mm 0.2792 ohns/Km 750 C Northern
Continuous current carrying capacity in Amp during 10 to 14 HRS for conductor of age Up to one year
Between one to Ten years
Beyond 10 years
47.5
252.46
263.43
269.12
45.0
268.06
279.70
285.48
40.0
296.87
309.67
315.64
32.5
335.18
349.38
355.60
20.0
390.01
405.95
412.51
47.5
244.49
254.83
260.71
45.0
260.56
271.61
277.57
40.0
290.12
302.39
308.50
32.5
329.21
342.94
349.28
20.0
384.89
400.42
407.07
47.5
237.01
246.76
252.82
45.0
253.56
264.05
270.17
40.0
283.85
295.62
301.86
32.5
323.70
336.99
343.43
20.0
380.19
395.33
402.07
47.5
230.37
239.58
245.82
45.0
247.36
257.36
263.63
40.0
278.33
289.65
296.02
32,5
318.87
331.77
338.31
20.0
376.09
390.89
397.70
47.5
231.59
240.89
247.10
45.0
248.50
258.58
364.83
40.0
279.33
290.74
297.09
32.5
319.75
332.72
339.24
20.0
376.83
391.69
398.49
47.5
229.65
238.80
245.06
45.0
266.74
256.63
262.93
40.0
277.73
289.01
295.39
32.5
488.42
513.25
525.82
20.0
581.71
609.99
622.97
47.5
341.41
359.68
372.02
45.0
370.17
389.85
402.94
40.0
421.94
443.98
556.32
32.5
488.82
513.68
526.24
20.0
582.05
610.35
623.32
47.5
342.99
361.37
373.65
45.0
370.63
391.40
403.65
40.0
423.22
445.35
457.66
Table 21-IV 21.7 Continuous Current Carrying Capacity of ACSR Conductors 1. 2. 3. 4. 5.
Code Name & Size Overall Diameter Resistance at 200 C Maximum Design Temp. of conductor Region
Month
January
February
March
April
May
June
July
Ambient Temperature in "C
ACSR 'Zebra' 28.62mm 0.06888 ohns/Km 750 C Northern
Continuous current carrying capacity in Amp during 10 to 14 HRS for conductor of age Up to one year
Between one to Ten years
Beyond 10 years
47.5
580.38
619.16
638.95
45.0
621.77
662.58
682.56
40.0
697.27
714.63
762.03
32.5
796.22
844.93
865.99
20.0
935.83
989.97
1012.02
47.5
551.61
588.83
609.60
45.0
595.01
734.33
655.17
40.0
673.52
716.50
737.59
32.5
775.50
822.96
844.57
20.0
918.26
971.29
993.76
47.5
524.11
559.85
581.67
45.0
569.61
607.53
629.26
40.0
651.18
692.89
714.68
32.5
756.19
802.48
824.63
20.0
902.01
954.00
976.87
47.5
499.18
533.61
556.45
45.0
546.75
583.44
606.03
40.0
631.29
671.86
694.31
32.5
739.13
784.40
807.05
20.0
887.76
938.84
962.07
47.5
503.78
538.45
561.09
45.0
550.96
587.87
610.29
40.0
634.94
675.71
698.04
32.5
742.24
787.70
810.25
20.0
890.35
941.60
964.76
47.5
496.46
530.74
553.70
45.0
544.27
580.81
603.50
40.0
629.14
669.58
692.11
32.5
737.29
782.45
805.15
20.0
886.23
973.21
960.48
47.5
497.55
531.89
554.80
August
September
October
November
December
45.0
545.26
581.86
604.51
40.0
630.00
670.49
692.99
32.5
738.02
783.23
805.91
20.0
886.84
937.86
961.11
47.5
500.54
535.04
559.82
45.0
547.99
584.74
607.28
40.0
632.27
672.99
695.41
32.5
740.04
785.27
807.99
20.0
888.52
939.65
962.86
47.5
528.75
564.74
586.37
45.0
573.88
612.04
633.61
40.0
654.92
696.84
718.51
32.5
759.41
805.90
827.96
20.0
904.71
956.88
979.68
47.5
543.19
579.94
601.03
45.0
587.20
626.10
647.20
40.0
666.63
709.22
730.52
32.5
769.53
816.63
828.40
20.0
913.23
965.93
988.52
47.5
56.66
604.69
624.94
45.4
608.98
649.08
669.46
40.0
685.89
729.59
750.32
32.5
786.28
834.38
855.71
20.0
927.38
980.98
1003.24
47.5
583.42
622.35
642.05
45.0
624.60
665.57
685.46
40.0
699.80
744.30
764.63
32.5
798.44
847.27
868.28
20.0
937.71
991.97
1013.98
Table 21-V 21.8 Continuous Current Carrying Capacity of ACSR Conductors 1. 2. 3. 4. 5.
Code Name & Size Overall Diameter Resistance at 200 C Maximum Design Temp. of conductor Region
ACSR 'Moose' 31.77mm 0.05595 ohms/Km 750 C Northern
Month
January
February
March
April
May
June
July
August
September
Ambient Temperature in °C
Continuous current carrying capacity in Amp during 10 to 14 HRS for conductor of age Up to one year
Between one to Ten years
Beyond 10 years
47.5
637.49
686.07
710.72
45.0
685.66
736.61
761.41
40.0
773.28
828.37
853.58
32.5
887.67
947.87
973.80
20.0
1048.65
1115.27
1142.39
47.5
601.14
648.10
674.14
45.0
652.00
701.39
727.39
40.0
743.59
797.21
823.37
32.5
862.93
920.77
947.44
20.0
1062.96
1092.32
1119.92
47.5
566.09
611.58
639.10
45.0
619.84
667.78
695.04
40.0
715.56
767.80
794.94
32.5
837.87
895.43
922.84
20.0
1006.84
1071.05
1099.18
47.5
534.03
578.23
607.27
45.0
590.70
637.38
665.88
40.0
690.48
741.51
769.58
32.5
816.55
872.91
901.08
20.0
989.17
1052.77
1080.98
47.5
539.97
584.40
713.15
45.0
596.08
642.98
671.25
40.0
695.08
746.34
774.22
32.5
820.45
877.09
905.05
20.5
992.39
1055.77
1084.29
47.5
530.51
574.56
603.78
45.0
587.52
634.06
662.70
40.0
687.75
738.66
766.83
32.5
814.25
87057
898.73
20.0
987.28
1050.36
1079.02
47.5
531.92
576.03
605.18
45.0
588.79
635.39
663.98
40.0
688.84
739.80
676.93
32.5
815.17
871.54
899.67
20.0
988.04
1051.16
1079.81
47.5
535.79
580.05
609.00
45.0
592.29
639.03
667.46
40.0
691.83
742.92
770.95
32.5
817.70
874.20
902.25
20.0
990.12
1053.37
1081.96
47.5
572.01
617.76
645.02
October
November
December
45.0
645.26
673.44
700.42
40.0
720.27
722.74
799.70
32.5
841.89
899.68
926.94
20.0
1010.19
1074.59
1102.63
47.5
590.43
636.93
663.41
45.0
642.14
691.08
717.45
40.0
734.96
788.15
814.61
32.5
854.50
912.94
939.83
20.0
1020.72
1085.73
1113.49
47.5
620.18
667.99
693.28
45.0
669.40
719.80
745.16
40.0
759.07
813.45
839.11
32.5
875.32
934.87
961.15
20.0
1038.22
1104.24
1131.54
57.5
641.30
690.06
714.57
45.0
689.21
740.33
765.01
40.0
776.42
831.67
856.79
32.5
890.41
950.76
976.62
20.0
1050.97
1117.72
1144.71
Related Documents 3h463d
Current Carrying Capacity Of Overhead Transmission Line Acsr Conductor 623y36
November 2019 210
Current Carrying Capacity Acsr Conductors 6so1p
November 2019 332
Current Capacity Of Acsr Conductors l106p
December 2019 85
Transmission Line Capacity Calculation 51303w
October 2019 143
Acsr Conductor 3o6228
April 2020 37