Delta MS 300M - Display Solar Power Calculator Specifications download pdf (Page 18)

DESCRIPTION

AC signals have waveforms that fluctuate repeatedly when viewed instantaneously.

Therefore, measuring the power values of AC signals requires averaging for each period in

a repeated interval, or averaging the data of several periods using a filtering process. The

WT3000 automatically selects the appropriate calculation method (one of the above two

methods) based on the data updating period. This approach ensures fast response and high

stability as suitable for the particular measurement objective.

 When the data updating period is 50ms, 100ms, 5s, 10s, or 20s

Measurement values are determined by applying an Average for the Synchronous Source

Period (ASSP) calculation to the sample data within the data updating period. (Note that this

excludes power integrated values WP, as well as current integrated value q in DC mode).

With ASSP, a frequency measurement circuit is used to detect the input signal period set as

the synchronous source. Sample data corresponding to an interval which is an integer

multiple of the input period are used to perform the calculation. Based on its fundamental

principles, the ASSP method allows measurement values to be obtained simply by

averaging an interval corresponding to a single period, so it is useful in cases where the

data updating period is short or when measuring the efficiency of low-frequency signals.

This method will not provide correct measurement values unless the period of the set

synchronous source signal is accurately sensed. Therefore, it is necessary to check whether

the frequency of the synchronous source signal has been accurately measured and

displayed. See the user’s manual for notes on the synchronous source signal and frequency

filter settings.

 When the data updating period is 250ms, 500ms, 1s, or 2s

Measurement values are determined by applying an Exponential Average for Measuring

Period (EAMP) calculation to the sample data within the data updating period. With EAMP,

the sample data are averaged by applying a digital filtering process. This method does not

require accurate detection of the input period. EAMP provides excellent measurement value

stability.

* See page 12 of the specifications for information on the relationship between the data updating

period and the lowest measurement frequency.

There are several types of power––active power, reactive power, and apparent

power. Generally, the following equations are satisfied:

Active power P = UIcosØ (1)

Reactive power Q = UIsinØ (2)

Apparent power S = UI (3)

In addition, these power values are related to each other as follows:

(Apparent power S)

= (Active power P)

+ (Reactive power Q)

(4)

U: Voltage RMS

I: Current RMS

Ø: Phase between current and voltage

Three-phase power is the sum of the power values in the individual phases.

These defining equations are only valid for sinewaves. In recent years, there has

been an increase in measurements of distorted waveforms, and users are

measuring sinewave signals less frequently. Distorted waveform measurements

provide different measurement values for apparent power and reactive power

depending on which of the above defining equations is selected. In addition,

because there is no defining equation for power in a distorted wave, it is not

necessarily clear which equation is correct. Therefore, three different formulas for

calculating apparent power and reactive power for three-phase four-wire

connection are provided with the WT3000.

 TYPE1 (method used in normal mode with older WT Series models)

With this method, the apparent power for each phase is calculated from equation (3), and reactive

power for each phase is calculated from equation (2). Next, the results are added to calculate the

power.

Active power:

PΣ=P1+P2+P3

Apparent power: SΣ=S1+S2+S3(=U1×I1+U2×I2+U3×I3)

Reactive power: QΣ=Q1+Q2+Q3

*S1, S2, and S3 are calculated with a positive sign for the leading phase and a negative sign for the lagging phase.

 TYPE2

The apparent power for each phase is calculated from equation (3), and the results are added together

to calculate the three-phase apparent power (same as in TYPE1). Three-phase reactive power is

calculated from three-phase apparent power and three-phase active power using equation (4).

Active power:

PΣ=P1+P2+P3

Apparent power: SΣ=S1+S2+S3(=U1×I1+U2×I2+U3×I3)

Reactive power:

 TYPE3 (method used in harmonic measurement mode with WT1600 and PZ4000)

This is the only method in which the reactive power for each phase is directly calculated using

equation (2). Three-phase apparent power is calculated from equation (4).

Active power:

PΣ=P1+P2+P3

Apparent power:

Reactive power:

QΣ=Q1+Q2+Q3

Automatically select the appropriate calculation for each data updating period

Selecting formulas for calculating apparent power and reactive power

QΣ=SΣ

-PΣ

SΣ=PΣ

+QΣ

(= (U1×I1)

-P1

+ (U2×I2)

-P2

+ (U3×I3)

-P3

500 × 560 × 705 mm (WDH)

/A: Keyboard and mouse mount

701960

Compact Instrument Cart

570 × 580 × 839 mm (WDH)

/A: Keyboard and mouse mount

701961

Deluxe Instrument Cart

467 × 693 × 713 mm (WDH)

701962

All-purpose Instrument Cart

 External dimensions of Yokogawa power meters (excluding protrusions)

WT3000

WT1600

WT210

WT230

PZ4000

*1 The back-side inputs protrude beyond the back shelves of the mounts.

426

213

426

177

132

177

450

400

379

450

Width (mm) Height (mm) Depth (mm)

✓

Compact mount

701960

Deluxe mount

701961

General-purpose

mount 701962

Top shelf

Middle shelf

Bottom shelf

Equipment not exceeding 450 (W) × 450 (D) × 300 (H) mm

Equipment not exceeding 450 (W) × 450 (D) × 240 (H) mm

* W: Width D: Depth H: Height

Maximum load: 20 kg on each shelf

Top shelf

Bottom shelf

Equipment not exceeding 450 (W) × 450 (D) × 400 (H) mm

Equipment not exceeding 450 (W) x 450 (D) × 400 (H) mm

* W: Width D: Depth H: Height

Maximum load: 50 kg on each shelf

*The photo shows the mount holding a DL7400.

Top shelf

Drawer

Slide table

Equipment not exceeding 457 (W) × 683 (D) mm

Equipment not exceeding 610 (W) × 380 (D) mm

Equipment not exceeding 380 (W) × 440 (D) mm

* W: Width D: Depth

Maximum load: 50 kg on each shelf

* These mount do not conform to CE marking.

Accessories

Instrument Carts.

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Delta MS 300M - Display Solar Power Calculator Specifications Page 18

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