Switch Gear
Content
TECHNICAL CLASS CONDUCTED BY Mr. SATCHIDANANDAM (KTPS) ON SWITCH GEAR SWITCH GEAR: MCC+PCC Previously Switchgear is having two levels and present they are in 3 levels. 1st level up to 415 volts 2nd level up to 3.3 kv/6.6kv 3rd level up to 11 kv (medium voltage) Each panel accommodate 6 chambers/8 chambers Size 2 - 8 nos. Size 4 - 6 nos. Size 8 - 2 nos. Main parts: 1. Bus bar chamber vertical and horizontal 2. Colour code R, Y, B with sufficient insulation on bus bar Rating: Fault rating for bus bar design is 50 KA/ 1 sec. Previously it is 31 KA/ 3 sec. Note: short circuit fault set point below 1 sec. Copper bus 50mm x 6mm Aluminium bus 50mm x 12 mm Cable out going to load is from right side of the panel. The following points should be considered in the panel 1 one set of auxiliary bus bar is arranged for a.c 230 v for space heaters. 2.one set of d.c. bus bar for 220 volts/110 volts. 3.one set of 24 volts a.c. bus. (When ever the motor is in off condition the 24 a.c.volts is connected to the motor interior winding to maintain the winding temperature at cold areas to avoid condensation. Above 37.5 KW.
Motors. Degree of Protection: IP CODE: (International Protection) IP follows two numbers of letters. 1st digit ‘0’ no protection. 1→ below 50mm particles allowed (hand protected). 2→ below 12.5mm (finger protection) 3→ below 2.5mm (tool protection) 4→ below 1 mm (tool protection) 5→ dust protection. 6→ dust protection 2nd letter indicates liquid protection 1→ water protection 2→ 30-degree angle water protection. 3→ 1 kg water pressures. Ex: IP 67 If motor keeps in the depth of one-meter water will not enter. (Actuator) MODULES: Utilization categories: SFU: SWITCH FUSE UNIT: AC –11; AC—12; AC—13 AC—21; AC—22; AC—23 1st letter 1 indicates one contact of fuse unit, 2 is two contacts open type 2nd letter indicates 1 is resistive load, 2 is slight inductive load, 3 is totally inductive load. The fuses are rating as Gg and are notation. Gg is meant for industrial where thermal over load protection is needed. Fusing of the fuse is 1.6 times the rated current. Am is meant for distribution side for short circuit protection and fusing of the fuse is 6.3 times the rated current. ACB- AIR CIRCUIT BREAKERS 400 A TO 6300 AMPS. ACBs are used above 150 H.P. motors. Breaking capacity is 40 KA, and making capacity is 10 KA. Over loading and short circuit current is more compared to the other breakers.
DUTY UTILIZATION CATEGORIES: AC 1, AC 2, AC 3 & AC 4 AC 1 – resistive load. AC 2 – slip ring induction motor. AC 3 – induction motor. S 1 – continuous duty. S 2 – 15 to 20 operations/minute. S3 – switching operations more than 30/minute (size of the motor increases) S4— inching operation. ACB Protection: If 50 H.P. motors is using instead of 30 H.P. motors the set point is to be adjust to the 30 H.P. loads only. OLR: over load relay Short circuit protection relay is used to minimize the extend damage of equipment and protect the surround equipment. Depending on the percentage impedance of the system/equipment the allowable short circuit current is 6 to 8 times of the rated current. Ensure the condition of the motor when supply fails (under voltage relay). Two supplies do not parallel when Mechanical interlock provide with casual key. SWITCH YARD CTs: 3 CORES ARE USED AS FOLLOWS: 1. Metering 2. Protection 3. Differential. If 5 cores are used as follows: 1. Metering. 2. 0.2 class accuracy metering (energy). 3. Protection. 4. Bus bar 5. Differential. SPECIFICATIONS: 1. Metering class 2. Protection class 3. Differential class (PS) purchase specification
Metering class: 0.1; 0.2; 0.5; 1.0; 3.0, 5.0 If we are using 1000/1 A C.T. Class 1.0 means the maximum allowable tolerance is +_ 10 amps. If the current exceeds more than rated current through C.T. it is over saturated it shows secondary current is ZERO. Protection class: 5 P 10; 5 P 15; 5 P 20 1st letter 5 is indicating the percentage of error. P is protection 10 is accuracy limit fault. Z % - 10% 10 times the normal current. Accuracy limit 10 times 5 P 10 – 10 KA Based on the percentage impedance we have to select 5 P10 to 5 P 20. (More cost) Differential class (PS) should match the other C.T. Generally PS class is KVP –500volts. Secondary resistance is 10 to 20 milli ohms, Magnetizing current is 30 ma. Saturation current is –VK/2 Accuracy of CT: 10% raise of volts is 50% raise of current of CT To know the notation of CT terminals: Metering class 5 to 10 volts saturation level. Protection class 80 to 100 volts. Differential class _ 500 volts. CT terminals should not be opened when the circuit is live. Produce abnormal voltage. PT terminals should not short when the circuit is in ON condition. Produce high current and damage the winding. Fuses are provided to PT.
PT fuses failure alarm monitoring relay 415/√3 / 110/√3 and 132kv/√3 / 110v/√3 Accuracy class: for metering class –80% to 120% (% error 0.1 to 0.3) Protection class: (5 to 120%) at low voltage level 3P, 5P When the system is healthy Io, Vo how do you differentiate with PT fuse failure. Vo is present and Io is zero PT fuse failure. CDG 11 for low voltage side IDMT relay – source end Numerical relay: Very inverse Extreme inverse Normal inverse What is the difference between the release and LV SWITCH DISCONNECTOR FUSE UNIT RELATED TERMS Ue - Rated Operational Voltage Ui - Rated Insulation Voltage Uimp- Rated Impulse Withstand Voltage Ie – Rated Operational Current Icw – Rated Short Time Withstand Current Icm – Rated Short-Circuit Making Capacity UTILISATION CATAGOERY AC 20 A/B: Connecting And Disconnecting Under No-Load Conditions AC 21 A/B: Switching Of Resistive Loads, Including Moderate Overloads AC 22 A/B: Switching Of Mixed Resistive And Inductive Loads, Including Moderate Overloads AC 23 A/B: Switching Of Motor Loads Or Other Highly Inductive Loads Where A – Frequent Operation B – Infrequent Operation Category AC 20 AC 21 Making -1.5Ie Make/Break -1.5Ie
AC 22 AC 23 WHERE Ie - Rated Operational Current
3Ie 10Ie
3Ie 8Ie
Motors. Degree of Protection: IP CODE: (International Protection) IP follows two numbers of letters. 1st digit ‘0’ no protection. 1→ below 50mm particles allowed (hand protected). 2→ below 12.5mm (finger protection) 3→ below 2.5mm (tool protection) 4→ below 1 mm (tool protection) 5→ dust protection. 6→ dust protection 2nd letter indicates liquid protection 1→ water protection 2→ 30-degree angle water protection. 3→ 1 kg water pressures. Ex: IP 67 If motor keeps in the depth of one-meter water will not enter. (Actuator) MODULES: Utilization categories: SFU: SWITCH FUSE UNIT: AC –11; AC—12; AC—13 AC—21; AC—22; AC—23 1st letter 1 indicates one contact of fuse unit, 2 is two contacts open type 2nd letter indicates 1 is resistive load, 2 is slight inductive load, 3 is totally inductive load. The fuses are rating as Gg and are notation. Gg is meant for industrial where thermal over load protection is needed. Fusing of the fuse is 1.6 times the rated current. Am is meant for distribution side for short circuit protection and fusing of the fuse is 6.3 times the rated current. ACB- AIR CIRCUIT BREAKERS 400 A TO 6300 AMPS. ACBs are used above 150 H.P. motors. Breaking capacity is 40 KA, and making capacity is 10 KA. Over loading and short circuit current is more compared to the other breakers.
DUTY UTILIZATION CATEGORIES: AC 1, AC 2, AC 3 & AC 4 AC 1 – resistive load. AC 2 – slip ring induction motor. AC 3 – induction motor. S 1 – continuous duty. S 2 – 15 to 20 operations/minute. S3 – switching operations more than 30/minute (size of the motor increases) S4— inching operation. ACB Protection: If 50 H.P. motors is using instead of 30 H.P. motors the set point is to be adjust to the 30 H.P. loads only. OLR: over load relay Short circuit protection relay is used to minimize the extend damage of equipment and protect the surround equipment. Depending on the percentage impedance of the system/equipment the allowable short circuit current is 6 to 8 times of the rated current. Ensure the condition of the motor when supply fails (under voltage relay). Two supplies do not parallel when Mechanical interlock provide with casual key. SWITCH YARD CTs: 3 CORES ARE USED AS FOLLOWS: 1. Metering 2. Protection 3. Differential. If 5 cores are used as follows: 1. Metering. 2. 0.2 class accuracy metering (energy). 3. Protection. 4. Bus bar 5. Differential. SPECIFICATIONS: 1. Metering class 2. Protection class 3. Differential class (PS) purchase specification
Metering class: 0.1; 0.2; 0.5; 1.0; 3.0, 5.0 If we are using 1000/1 A C.T. Class 1.0 means the maximum allowable tolerance is +_ 10 amps. If the current exceeds more than rated current through C.T. it is over saturated it shows secondary current is ZERO. Protection class: 5 P 10; 5 P 15; 5 P 20 1st letter 5 is indicating the percentage of error. P is protection 10 is accuracy limit fault. Z % - 10% 10 times the normal current. Accuracy limit 10 times 5 P 10 – 10 KA Based on the percentage impedance we have to select 5 P10 to 5 P 20. (More cost) Differential class (PS) should match the other C.T. Generally PS class is KVP –500volts. Secondary resistance is 10 to 20 milli ohms, Magnetizing current is 30 ma. Saturation current is –VK/2 Accuracy of CT: 10% raise of volts is 50% raise of current of CT To know the notation of CT terminals: Metering class 5 to 10 volts saturation level. Protection class 80 to 100 volts. Differential class _ 500 volts. CT terminals should not be opened when the circuit is live. Produce abnormal voltage. PT terminals should not short when the circuit is in ON condition. Produce high current and damage the winding. Fuses are provided to PT.
PT fuses failure alarm monitoring relay 415/√3 / 110/√3 and 132kv/√3 / 110v/√3 Accuracy class: for metering class –80% to 120% (% error 0.1 to 0.3) Protection class: (5 to 120%) at low voltage level 3P, 5P When the system is healthy Io, Vo how do you differentiate with PT fuse failure. Vo is present and Io is zero PT fuse failure. CDG 11 for low voltage side IDMT relay – source end Numerical relay: Very inverse Extreme inverse Normal inverse What is the difference between the release and LV SWITCH DISCONNECTOR FUSE UNIT RELATED TERMS Ue - Rated Operational Voltage Ui - Rated Insulation Voltage Uimp- Rated Impulse Withstand Voltage Ie – Rated Operational Current Icw – Rated Short Time Withstand Current Icm – Rated Short-Circuit Making Capacity UTILISATION CATAGOERY AC 20 A/B: Connecting And Disconnecting Under No-Load Conditions AC 21 A/B: Switching Of Resistive Loads, Including Moderate Overloads AC 22 A/B: Switching Of Mixed Resistive And Inductive Loads, Including Moderate Overloads AC 23 A/B: Switching Of Motor Loads Or Other Highly Inductive Loads Where A – Frequent Operation B – Infrequent Operation Category AC 20 AC 21 Making -1.5Ie Make/Break -1.5Ie
AC 22 AC 23 WHERE Ie - Rated Operational Current
3Ie 10Ie
3Ie 8Ie
