Power Factor Regulator User's Guide

1. General Description

The Mikro Power Factor Regulator (PFR) is designed for optimizing reactive power compensation by continuously measuring system reactive power and compensating it through capacitor bank switching. It utilizes numerical techniques to precisely measure phase difference between current and voltage, even with harmonics present. The regulator features an intelligent automatic switching program to improve efficiency and reduce switching operations. It ensures even distribution of capacitor bank usage for uniform aging of capacitors and contactors. The four-quadrant operation capability allows it to function correctly during active power feedback to the mains from regenerative sources. The PFR can measure total harmonic distortion (THD) and trigger alarms for high THD levels, under/over compensation, under/over current, and under/over voltage. Mobile app connectivity via NFC and RS485 Modbus RTU protocol (with NX-M1 module) are available for monitoring and configuration.

2. Measurement

The PFR displays various system parameters:

• [PF] Cos φ: Displays the displacement power factor of the system.
• [U] Voltage: Displays the true-rms value of the voltage measurement (Line to Neutral or Line to Line).
• [A] Current: Displays the true-rms value of the primary current. The primary ratio must be set according to the external 5A current transformer ratio.
• [F] Frequency: Displays the frequency measurement of the voltage system.
• [t.A] Current THD / [t.U] Voltage THD: Displays the total harmonic distortion of current or voltage, calculated using the formula: THD = √(Σ(i_n)²)/i₁ where i_n is the nth order harmonic and i₁ is the fundamental current/voltage. This measurement requires the total load to be at least 5% of the rated load.
• [P.F.] Power Factor: Displays the power factor of the system.
• [P.A] Active Power / [P.r] Reactive power / [P.S] Apparent power: Displays the active, reactive, or apparent power of the load.

3. MENU

[S.C] System Configuration

Key configuration parameters include:

• Primary CT: Setting for the primary current transformer ratio (_/5A).
• Set Cos φ: Target power factor for automatic mode.
• Smallest Cap: Hysteresis setting based on the smallest capacitor size.
• Sensitivity: Sets the switching speed.
• Reconnection Time: Safety lockout time for capacitor discharge.
• Switch Program: Selection of four switching algorithms: Manual [n-A], Rotational [rot], Automatic [Aut], or Four-quadrant [Fqr].
• [r.S] Rated Step: Programmable capacitor steps.
• Fan Output [FAn]: Configures fan output.
• Alarm Output [ALA]: Configures alarm output.

[S.S] System Setting

Further system settings include:

• Rate Voltage: Sets the system voltage type (Line to Neutral [L-N] or Line to Line [L-L]).
• Rate Frequency: Sets the system frequency (50Hz or 60Hz), with an auto-trace option.
• System Coupling: Configures standalone [ALN], master [CTL], or slave [SLU] unit operation, or input control for master/slave activation.
• Input Control: Master and Slave activation control via Digital Input.

Front Panel Description

The PFRNX front panel includes:

• A 2-digit numeric display (a) for mode indication.
• CAP and IND indicators (b) to show capacitive or inductive power factor.
• An AUTO/MANUAL mode indicator (c) (LED ON for Auto, OFF for Manual).
• An ALARM indicator (d) that lights up when an alarm message is present.
• A 3-digit numeric display (e) for parameter values or alarm messages.
• DMD ON and DMD OFF indicators (f) showing capacitor bank switching status.
• Prefix multipliers (g) like KILO (10³) and MEGA (10⁶).
• A STEP OUTPUT indicator (i) showing the ON/OFF status of capacitor steps.
• An NFC tag area (j) for mobile communication.
• Navigation buttons: UP (k), ENTER (l), DOWN (m), and ESC (n).
• The device model, e.g., PFR160NX, is displayed.

4. Description of Alarm Parameters

The PFR provides various alarm functions, detailed in Table 1:

• THD Voltage/Current: Alarms when total harmonic distortion exceeds set thresholds.
• Undercurrent/Overcurrent: Alarms when current falls below or exceeds set values.
• Undervoltage/Overvoltage: Alarms when voltage falls below or exceeds set values.
• Cap Size Error: Indicates inability to reach target power factor due to unsuitable capacitor steps.
• Undercompensate/Overcompensate: Alarms when power factor remains low (all caps ON) or high (all caps OFF).
• Step Error: Detects potential issues with capacitor steps (requires auto smallest cap setting).
• No Voltage Release: Disconnects all steps if voltage is absent.
• CT Polarity Error: Detects incorrect CT connection polarity.
• Clock Loss: Indicates loss of timekeeping (requires NX-M1 module).
• EEPROM Error: Indicates a memory error (contact manufacturer).
• Step On Timer/Counter: Service alerts for capacitor step usage time or count (requires NX-M1 module).

Table 1 details specific settings, delay times, and programmable output options for each alarm.

5. Automatic CT Polarity Detection

During startup, the PFR can automatically detect and correct reversed CT polarity if set to Rotational or Automatic switch programs. This feature is disabled for Four-quadrant switching.

6. Programming Lock

A programming lock feature prevents accidental changes to control parameters. To lock/unlock, press and hold ENTER and DOWN buttons until [LOC] (locked) or [CLr] (unlocked) is displayed.

7. NFC Communication

NFC communication allows users to read parameters and change settings via a mobile app. Users need to download the PFRNX app and tag their mobile device to the PFR's NFC area.

8. NX-M1 Module

The NX-M1 module enables clock functions and RS485 protocol communication, allowing for recording of actions and alarms.

9. Application of Master and Slave PFR

With the NX-M1 module, PFR units can operate in Master/Slave configurations to increase step capacity or manage multiple feeds. Diagrams illustrate these applications, showing system extension and two-feed setups.

• Diagram 1 - Example of PFRs operate in step extension system: Shows two PFRs linked to expand step control.
• Diagram 2 - Example of PFRs operate in two feeds system: Illustrates two PFRs operating independently or as master/slave in a dual-feed scenario.

10. Shortcut to Manual Switch Program

The switch program can be temporarily set to manual mode by pressing and holding the ESC button for 3 seconds. The AUTO indicator will turn off. Capacitor steps can be controlled using UP/DOWN buttons. The system reverts to the configured program after 1 hour of inactivity.

11. Intelligent Capacitor Step Selection

In automatic or four-quadrant modes, the PFR selects capacitor steps with less activity for switching ON or more activity for switching OFF, if multiple steps have the same VAR value. This function operates after the smallest cap value is confirmed.

12. Step On Timer and Step On Counter

The PFR records capacitor step operating hours and counts. These can be accessed via the NFC app or RS485 communication (with NX-M1). Step on timer/counter alarms can be set as service alerts, and records can be reset through the app or communication.

13. Harmonic

The PFR measures harmonics up to the 15th order. Harmonic measurements can be retrieved via NFC app or RS485 communication.

14. Reset to Factory Default

To reset all parameters to factory defaults, power off the PFR, then press and hold UP and DOWN buttons simultaneously while powering on. Hold for over 3 seconds. The display will show [dEF] for 2 seconds.

15. Guide on Controlling PFR

This section provides a navigation flow for accessing various measurement displays and menu modes, including System Configuration, System Setting, Rated Step, Alarm Setting, Programmable Alarm, Programmable Output, and Communication Setting. It also includes examples for setting Primary CT, temporarily switching to manual mode, and reading multiple alarm messages.

16. Technical Data

17. Case Dimensions

The device has the following dimensions:

• FRONT: 145mm x 145mm
• SIDE: 78mm depth
• PANEL CUTOUT: 137mm x 137mm

18. Typical Connection Diagram

Diagram 3 illustrates the typical connection for a PFR unit, showing wiring for auxiliary supply (L1, L2, L3, N), current transformer (CT P1, P2), voltage inputs (20, 23, 24, 25), and capacitor bank step outputs (1-16, 15, 16). It also indicates the connection for the NX-M1 External Plug-in Module.

Thing to Setup and Verify Before Run

Before operating the PFRNX Power Factor Regulator, perform the following checks:

1. Check CT Setup: Ensure the CT is installed before the capacitor bank and load. Verify correct polarity connection between the secondary CT and PFRNX terminals (No.34 and No.35) as per the connection diagram. Set the Primary CT in PFRNX according to the primary current ratio (_/5A).
2. Check Voltage Setup: If measuring Phase-to-Phase voltage, set the voltage system to [L-L]. Connect YELLOW phase to terminal block No.23, BLUE phase to No.20, and ensure CT is on the RED phase line. If measuring Phase-to-Neutral voltage, set the voltage system to [L-N]. Connect RED phase to terminal block No.23, NEUTRAL phase to No.20, and ensure CT is on the RED phase line. Set the frequency setting to [60] if operating at 60Hz, otherwise set to [50].
3. Check Step Output Setup: For unused steps, it is recommended to disable them in the PFRNX rate step setting to prevent potential step error alarms. Ensure terminal block No.18 is connected to Live voltage.
4. Check Aux Power Setup: Verify that the voltage supplies to the Aux terminals (No.24 and No.25) are within the range of 100VAC to 415VAC or 140VDC to 340VDC.