Class 300 Equipment CBS 305, 320 Current Boost Systems CBS 320 Current Transformer CBS 305 The CBS 305 and CBS 320 Current Boost Systems are electronic devices designed to provide the Basler APR series of static voltage regulators with power to sustain exciter current when severe overloading of brushless generators occurs such as during motor starting or during short circuit conditions. Power for the current boost systems is derived from a power CT installed in two phases of the generator output. FEATURES Instantaneous response to short circuits. DESCRIPTION Page 2 SPECIFICATIONS Pages 2 through 4 Up to 7.2 A field boost power. Actuated when the generator voltage drops too low to maintain field current. Compatible with Frequency Compensation. Boost is inhibited by low frequency. For 50 or 60 Hertz brushless generators. Each model covers a wide range of generator application. ORDERING Page 4 OUTLINE DRAWINGS Pages 7 and 8 Totally encapsulated to eliminate the effects of vibration, dust, or moisture. CSA approved. P. O. BOX 269 HIGHLAND, ILLINOIS, U.S.A. 62249 PHONE 618-654-2341 FAX 618-654-2351 SRR-3 12-87
The Current Boost System consists of a current boost module auto-and a current transformer (CT). The system provides supplemental excitation source with the regulator which allows the field to receive full forcing during generator overloading and short circuits. The Current Boost System allows three wire and four wire generators to provide current during sustained single phase and multiple phase line-to line faults. The CBS also permits four wire generators to support phase A and C line to neutral faults. Phase B line-to-neutral faults will also have fault sustaining capabilities since the regulator and CBS input power is taken from the other unshorted phases. The Current Boost Module uses the CB+ and CBoutputs of the APR regulator as a turn-on signal. Boost power to the module is supplied from a CT installed in phase A and C of the generator output. During short circuits, the CT is the source of all excitation current for the generator - see figure 2. Because the APR regulator sensing is used to turn the boost on and off, the Current Boost System operating OUTPUT POWER DC Output Power Field Resistance For Use DC Volts DC Amps Ohms Ohms Model With Range (min) (max) CBS305 APR63-5 90-120 7.2 12.5 50 CBS320 APR1255 188-248 7.2 25 100 MAXIMUM INPUT CURRENT FROM CT: CBS 305 and CBS 320: 7A continuous CBS 305: 33A for 30 seconds CBS 320: 45A for 30 seconds POWER DISSIPATION: CBS 305 and CBS 320: 24 watts in non-boost mode CT-BE21331-001: 25 watts maximum CT-BE21433-001: 35 watts maximum CT-BE21432-001: 70 watts maximum TRANSIENT RESPONSE: Less than 2 cycles from regulator s boost signal until boost output reaches 90Vdc. DESCRIPTION SPECIFICATIONS level is automatically adjusted to the nominal generator voltage. The Current Boost System also follows the regulator s underfrequency curve to allow the prime mover to pick up large loads in one step. To verify that the available CTs will accommodate the generator s output cable, refer to HOW TO ORDER - Current Transformer. Three CTs are available: a.be21331-001 for use with the CBS 305 only and on generators with rated line currents up to 800A. b.be21433-001 for use with the CBS 320 on generators with rated line currents up to 800A. c.be21432-001 for use with either the CBS 305 or CBS 320 on generators with rated line currents up to 2400A. The CBS 305 and CBS 320 are totally encapsulated to eliminate all effects of moisture, dust, vibration, and shock as hazards to operation. CT SECONDARY TURNS: BE21331-001: Terminals 1 and 2-209 turns BE21433-001: Terminals 1 and 2-209 turns BE21432-001: Terminals 1 and 2-308 turns Terminals 1 and 3-616 turns CONTROL SIGNAL FROM APR REGULATOR: 10mA, 1.5Vdc SHOCK: Withstands 15 Gs in each of three mutually perpendicular planes. VIBRATION: Withstands the following vibration spectrum: Frequency Acceleration 5-26 Hz 1.2 G 26-52 Hz 0.036 in. displacement 52-260 Hz 5 G CT SECONDARY INSULATION RATING: 2500 Vac HI-Pot STORAGE TEMPERATURE: -65 C (-85 F) to +85 C (+185 F) OPERATING TEMPERATURE RANGE: -40 C (-40 F) to +60 C (+140 F) 2 HUMIDITY: Totally protected from humidity and condensation by encapsulation.
SPECIFICATIONS, continued WEIGHT: Current Boost Module: CBS 305-2.6 Ibs. (1.2kg) net 3.6 Ibs. (1.6kg) shipping See Figure 3 for dimensions. CBS 376-6.3 Ibs.(2.9kg) net 8 Ibs, (3.6kg) shipping See Figure 4 for dimensions. Current Transformers: BE21331-001 - See Figure 5 for dimensions. 15.5 Ibs. (7.lkg) net 17 Ibs. (8kg) shipping BE21433-001 - 28 Ibs. (13kg) net 31 Ibs. (14kg) shipping See Figure 6 for dimensions. BE21432031-44 Ibs. (2Okg) net 55 Ibs. (25kg) shipping See Figure 7 for dimensions. Figure 2 - Typical Interconnection Diagram 3
SPECIFICATIONS, continued SAMPLE SPECIFICATION: A current boost system shall be provided with the Basler APR 63-5 voltage regulator to sustain exciter field current during severe generator output overloads or short circuit. The operation of the current boost system shall be controlled by the voltage regulator. by a CT installed in two phases of the generator output. The current boost system shall be a Basler Electric Company Mode CBS 305 current boost system, with a current transformer selected based on Basler recommendation and generator performance data. Power for the current boost system shall be provided HOW TO ORDER - Current Boost System: When the CBS is Order to be used with APR63-5 CBS 305 APR125-5 CBS 320 HOW TO ORDER - Current Transformer (CT): Follow the step-by-step procedure below to select the proper turns-ratio for your application. Based on the resulting turns-ratio, wire or bus size, and rated generator output current, determine the part number of the CT having the proper rating and window size. Step 1. Calculate the exciter field current during generator short circuit: I Field = E/R f Where: I Field = Exciter field Current at short Circuit. R f = Exciter field resistance from generator data. E = CBS field forcing voltage (90 Vdc for CBS 305,180 Vdc for CBS 320) Step 2. From the generator manufacturer s short circuit saturation data (plot of exciter field current versus line amps with generator output short circuited), determine the generator three phase line current during a short circuit that would result from the exciter field current calculated in step 1. If for your generator system: This results in excessive generator linecurrent. Then proceed to: Step 3A This results in acceptable generator linecurrent. Step 38 Step 3A. a. Determine the acceptable generator three phase line current at short circuit (typically 300% of nominal). Refer to Table 1 and locate the range that covers this value in column 1. b. Using the generator manufacturer s short circuit data (plot of exciter field current versus line amps with the generator output short circuited), determine the exciter short circuit field current required to generate the acceptable generator line current (1 2 ). Refer to Table 1 and locate the current value equal to this value in column 3. If the desired field current is in between the column 3 values, go to the next higher value. c. Check that the rated generator full load line current doesn t exceed the maximum continuous line current in column 2. If the generator full load line current does exceed the maximum continuous line current rating, consult with the factory. d. To obtain reduced field current, place a current limiting resistor in series with the exciter field. Calculate the value of this resistor as follows: R S = E/I 2 - R f Where: R S = Value of series field resistance to be added (in ohms). This resistance must not be so great as to restrict normal forcing. E = CBS field forcing voltage (90 Vdc for CBS 305, and 180 Vdc for CBS 320). I 2 = Field current required to produce acceptable generator line current at short circuit from b. above. R f = Exciter field resistance from generator data. e. Proceed to step 4. Step 3B. 4
HOW TO ORDER, continued a. In Table 1. column 1, locate the range of the generator three phase short circuit line current that covers the value determined in step 2. b. Check that rated generator line current does not exceed the maximum continuous line current in column 2. c. In Table 1, column 3, locate the exciter field current that is closest to the value determined in step 1. If the value is between the values in column 3, go to the next higher value. d. Proceed to step 4. a. Find the turns-ratio at the point of intersection of the values found in step 3. b. The first numeral of the turns-ratio indicates the number of turns of each of two (2) generator lines that pass through the CT window. The second number indicates secondary turns provided by the CT terminals. Step 5. Verify that the CT window size is sufficient for the generator conductors by comparing the conductor cross-section (including insulation) with the window area shown in figure 5, 6, or 7. Step 4. Column 1 Column 2 Column 3 3 Phase Line Maximum Exciter Field Current at Rated CBS Current @ Continuous Output Voltage (90 Vdc for CBS 305 or Short Circuit Line Current 180 Vdc for CBS 320) 1.8Adc 3.6Adc 7.2Adc 35-70 25 8:209 16:209 32:209 70-140 50 4:209 8:209 16:209 140-275 100 2:209 4:209 8:209 275-550 200 1:209 2:209 4:209 550-1100 400 1:209 1:209 2:209 BE21331-031 for CBS 305 or BE21433-001 for CBS 320. 1100-2200 800 1:209 1:209 1:209 1600-3200 1200 1:616 1:616 1:308 BE21432-001 for CBS 305 3200-6400 2400 1:616 1:616 1:616 and CBS 320 Table 1 - Turns-Ratio Selection 5
EXAMPLE of the HOW TO ORDER - (CT) procedure on page 4. Sample Generator Data: 100KW, 125kVA, 60Hz, 3-phase, 480V, 150A at full rated load, 15 ohm field. IF = 5.14Adc @ 300% short circuit (450A line) IF = 6.0 Adc @ 350% short circuit (525A line) (Step 1) Determine the field current that will be provided by a Basler CBS 305 during short circuit: Where: I F = E 900 Vdc = = 6.0A R 15 ohms I F = Field Current E = APR63-5/CBS305 Maximum dc output voltage. R = Exciter field resistance. (Step 2) From generator manufacturer s data, you determine that the exciter field current of 6.0A from the CBS 305 would result in a short circuit line current of 525A- for your generator system you consider this to be: EXCESSIVE (Step 3A) You determine that 450A would constitute an acceptable generator line current at short circuit. From the generator manufacturer s data, you determine that an exciter field current of 5.14A is required for the generator system to deliver an acceptable 450A at short circuit. In Table 1, column 1, the value of 450A is between the values of 275 to 550A. Draw a horizontal line from this point across the chart. In Table 1, column 3, the value of 7.2A is the closest higher value to the required value of 5.14A (from step 3A). Draw a vertical line from this point down the chart. In Table 1, column 2, the maximum continuous line current of 200A is greater than the full load line current of 15OA. therefore, the limits of the CT are not exceeded. Determine the necessary resistance to be added to the exciter field to achieve the 5.14A exciter field current: E R S = - R f = 90 Vdc - 15 ohms = 17.5-15 ohms I 2 5.14 = 2.5 ohms Note - The series resistance must not be so great as to restrict normal forcing. (Step 4) From Table 1, the intersection of the two lines (from step 3A) is the turnsratio, 4:209. 4 turns on the primary: 209 turns on the secondary. (Step 5) The first numeral of the turns-ratio (4), the number of conductors per phase (1) and the number of phase (2) multiplied together results in: 8 conductors (through the CT window). From the generator manufacturer s data, 0.537 is the conductor diameter; therefore, for 8 conductors the CT window must be at least 0.537 in X 4.30 inches. Basler CT P/N BE21331-001 is 0.9 in. X 4.375 in. and meets the requirement. ACCEPTABLE (Step 38) In table 1, column 1, the value of 525A (from step 2) is between the values of 275-550A. Draw a horizontal line from this point across the chart. In Table 1, column 2, the maximum continuous line current of 200A is greater than the full load line current of 150A, therefore, the limits of the CT are not exceeded. n Table 1, column 3, the value of 7.2A is the next higher value after the required value of 6.OA (from step 1). Draw a vertical line from this point down the chart. (Step 4) From Table 1, the intersection of the two lines (from step 3A) is the turns-ratio, 4:209, 4 turns on the primary: 209 turns on the secondary (Step 5) The first numeral of the turns-ratio (4) the number of conductors per phase (1) and the number of phases (2). multiplied together results in: 8 conductors (through the CT window). From the generator manufacturer s data, 0.537 is the conductor diameter; therefore, for 8 conductors, the CT window must be at least 0.537 in. x 4.30 in. Basler CT P/N BE21331-001 is 0.9 in. x 4.375 in. and meets the requirement. 6
OUTLINE DRAWINGS Figure 3 - Outline Drawing, Current Boost Module (CBS 305) Figure 4 - Outline Drawing, Current Boost Module (CBS 320) 7
OUTLINE DRAWINGS Figure 5 - Outline Drawing, Current Transformer P/N BE21331-01 Figure 6 - Outline Drawing, Current Transformer P/N BE21433-001 Figure 7- Outline Drawing, Current Transformer P/N BE21432-001 Note: All dimensions in inches (millimeters) All drawings and data subject to change without notice. ROUTE 143, BOX 269, HIGHLAND, ILLINOIS U.S.A. 62249 P.A.E. Les Pins, 67319 Wasselonne Cedex FRANCE PHONE 618-654-2341 FAX 618-654-2351 PHONE (33-3-88) 87-1010 FAX (33-3-88) 87-0808 http://www.basler.com, info@basler.com