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Three Phase Power Measurement, Two Wattmeter Method, Two Lamp Method.
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Group- 03 Topics: • Three Phase Power Measurement Methods (Two Wattmeter Method) • Sequence Identification (Two Lamp Method) • Group Members • 1. TanvirHasnain • ID- ASH 2117024M • 2.NajiurRahman • ID- MUH 2117026M • 3. Md. RijviKasem • ID- MUH 2117027M • 4. Fahim Jahangir • ID- ASH 2117028M • 5. Kamen Tripura • ID- ASH 2117030M • 6. MD. IstihadBhuiyan • ID- MUH 2117031M • 7. Abdullah Al Mamun • ID- ASH 2117033M
FAHIM JAHANGIRID: ASH2117028M PRESENTER
Three Phase System The system which has three phases, i.e., the current will pass through the three wires, and there will be one neutral wire for passing the fault current to the earth is known as the three phase system. (Fig 1.1) Figure 1.1
Three Phase System The three phase system induces in the generator which gives the three phase voltage of equal magnitude and frequency. The 120º phase difference of the three phases is must for the proper working of the system. Otherwise, the system becomes damaged.
Types of Connections in Three-Phase System The three-phase systems are connected in two ways, i.e., the star connection and the delta connection. Star Connection: The star connection requires four wires in which there are three phase conductors and one neutral conductor. Delta Connection: The delta connection has three wires, and there is a no neutral point.
Md. RijviKasemID: MUH2117027M PRESENTER
Three Phase Power Measurement Methods The power output of a three-phase power system remains to be constant, and it never drops into zero. The power in a three phase load can be measured by following methods: Three wattmeter method. Two wattmeter method. One wattmeter method. For now, we will discuss about Two wattmeter method to measure Three Phase power.
Two Wattmeter Method Two WattmeterMethod can be employed to measure the power in a three phase, three-wire star or delta connected the balanced or unbalanced load.
The total instantaneous power absorbed by the three loads Z1, Z2 and Z3, is equal to the sum of the powers measured by the two wattmeters, W1 and W2.
TanvirHasnainID: ASH2117024M PRESENTER
Measurement of Power by Two Wattmeter Method in Star Connection Considering the above figure (A) in which Two Wattmeter W1 and W2 are connected, the instantaneous current through the current coil of Wattmeter, W1 is given by the equation shown below: The instantaneous potential difference across the potential coil of Wattmeter, W1 is given as: Fig (A) Instantaneous power measured by the Wattmeter, W1 is The instantaneous current through the current coil of Wattmeter, W2 is given by the equation:
Measurement of Power by Two Wattmeter Method in Star Connection The instantaneous potential difference across the potential coil of Wattmeter, W2 is given as: Instantaneous power measured by the Wattmeter, W2 is: Therefore, the total power measured by the two wattmeters W1 and W2 will be obtained by adding the equation (1) and (2). Fig (A)
Measurement of Power by Two Wattmeter Method in Delta Connection The instantaneous current through the coil of the wattmeter, W1 is given by the equation: The instantaneous potential difference across the potential coil of Wattmeter, W1will be: Therefore, the instantaneous power measured by the wattmeter, W1 will be given as: The instantaneous current through the current coil of the Wattmeter, W2 is given as: The instantaneous potential difference across the potential coil of wattmeter, W2 :
Measurement of Power by Two Wattmeter Method in Delta Connection Therefore, the instantaneous power measured by Wattmeter, W2 will be: Hence, to obtain the total power measured by the two wattmeter the two equations, i.e. equation (3) and (4) has to be added. Where P is the total power absorbed in the three loads at any instant.
ABDULLAH AL MAMUNID: ASH2117033M PRESENTER
PhaseSequence The phase sequence is the time order in which the voltages pass through their respective maximum values. For a three-phase system, there are only two possible phase sequences: a-b-c and a-c-b , corresponding to the two possible directions of alternator rotation. Figure: Phase Sequence Figure: Three Phase Sinusoidal Currents
Phase Sequence Identification Types of Phase Sequence Indicator: The phase sequence indicator is of two types. They are : 1. Rotating Type 2. Static Type (Example-Two Lamp Method) Static Type Phase Sequence Indicator
NajiurRahmanID: MUH2117026M PRESENTER
Two Lamp method The two lamp method consists of two lamps and an inductor. The brightness of the lamp depends on the voltage drops occurs across it.
Let the phase sequence of the supply is RYB, and the relationship of the phase concerning the voltage is VRY, VBY and VRB as shown in the figure. The equation gives the value of current-
Testing the Method Using Inductor - If the phase sequence of the supply is RYB, the Lamp 1 will glow, and the lamp 2 will not glow. - And for the reverse phase sequence, the lamp 1 will be darker, and 2 will glow.
Testing the Method Using Inductor - If the phase sequence of the supply is RYB, the Lamp 1 will light, and the lamp 2 will be off. - And for the reverse phase sequence, the lamp 1 will be off, and 2 will be light.
KAMEN TRIPURAID: ASH2117030M PRESENTER
Applications of Three Phase Power System • To this point, some of the more specific applications of 3 phase power system include: • Manufacturing & Heavy Machinery
Power Grids • Data Centers
Mobile Towers • Aircraft
MD. IstihadBhuiyanID: MUH 2117031M PRESENTER
Advantages of Three Phase System A three-phase circuit provides greater power density than a one-phase circuit at the same amperage, keeping wiring size and costs lower.
CONCLUSION In a three phase system we must fix 120º phase difference for the proper working of the system. Otherwise, the system becomes damaged. Both balanced and unbalanced load can be balanced using two wattmeter method. In two lamp method lamp 1 & lamp 2 are show different results for different phase sequences.
