3.1.9 Meter Reactive Power Pulse Constant
Q_K_t defines the meter test constant, which is the amount of reactive energy signified by one output pulse. Q_K_t is in units of [VARh/pulse].
Q_K_t is stored in uQ8.24 format.
In Europe and Asia, the pulse constant, MC, is used where MC is in units of [pulses/kVARh]. First, convert from units of MC to units of Q_K_t (Q_K_t = 1000/MC), then convert into uQ8.24 format by multiplying by 2^24.
For example, if MC = 800 pulses/kVARh, then Q_K_t = 1000/800 = 1.25 VARh/pulse, and Q_K_t = round[1.25 x 2^24] = 20971520 = 0x01400000
The frequency of pulse output generated depends on the quantity of energy measured and the defined pulse constants (P_K_t, Q_K_t, and I_K_t). It is important to note that there is a limitation on the maximum frequency of pulse occurrence: the pulse period duration cannot exceed the sum of the pulse width plus an additional 500 microseconds.
For example, if the pulse width is set at 500 microseconds, the maximum pulse frequency that can be attained is 1 kHz. On the other hand, if the pulse width is reduced to 50 microseconds, the pulse frequency can increase to a maximum of 1.818 kHz.
Updates to Q_K_t take effect at the next negative zero-crossing (narrow-band filtered version) of the present control phase voltage channel.
| Name: | Q_K_t |
| Offset: | Metrology_Reg_In[10] |
| Property: | Read-Write |
| Bit | 31 | 30 | 29 | 28 | 27 | 26 | 25 | 24 | |
| Q_K_t[31:24] | |||||||||
| Access | R/W | R/W | R/W | R/W | R/W | R/W | R/W | R/W | |
| Reset | |||||||||
| Bit | 23 | 22 | 21 | 20 | 19 | 18 | 17 | 16 | |
| Q_K_t[23:16] | |||||||||
| Access | R/W | R/W | R/W | R/W | R/W | R/W | R/W | R/W | |
| Reset | |||||||||
| Bit | 15 | 14 | 13 | 12 | 11 | 10 | 9 | 8 | |
| Q_K_t[15:8] | |||||||||
| Access | R/W | R/W | R/W | R/W | R/W | R/W | R/W | R/W | |
| Reset | |||||||||
| Bit | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 | |
| Q_K_t[7:0] | |||||||||
| Access | R/W | R/W | R/W | R/W | R/W | R/W | R/W | R/W | |
| Reset | |||||||||