Capacitor Changeover Controller

The JKW-F3 Capacitor Changeover Controller is an automatic reactive power compensation split-phase controller built around a high-performance microprocessor. This sophisticated product simultaneously acquires three-phase voltage and three-phase current signals. A single unit can provide up to 24 output circuits, enabling full split-phase compensation, full common-phase compensation, or a mixed common-phase + split-phase compensation strategy. It also offers 12 different capacitor combination modes (capacity coding). Users can select and modify control parameters, which are permanently saved once set. The product uses a combined control method based on fundamental power factor and fundamental reactive power to switch capacitor banks, resulting in stable, oscillation-free operation. It is insensitive to harmonics, correctly displays electrical data, and controls switching accurately. Featuring a character LCD screen, this product has a friendly human-machine interface, is easy to operate, has an aesthetically pleasing design, and is suitable for automatic control of reactive compensation in 0.4KV systems. Its functional characteristics are comprehensive:

• 1. Using fundamental power factor and reactive power for control avoids multiple forms of switching oscillation and ensures correct data display and switching control even in the presence of harmonics.
• 2. High-accuracy power factor measurement with a wide display range.
• 3. 12 capacitor capacity coding options for user selection.
• 4. A single Capacitor Changeover Controller can control up to 24 output circuits, allowing arbitrary modification of the number of split-phase and common-phase circuits within this limit.
• 5. Large-screen LCD display with Chinese prompts for convenient, fast operation; all parameters have corresponding Chinese characters, and data is shown digitally.
• 6. Features Automatic and Manual operating modes with memory function.
• 7. Includes one passive alarm output port, with the alarm event selectable via programming.
• 8. Control parameters are memorized and not lost during power outages.
• 9. Protection functions include over-voltage, under-voltage, voltage harmonic limit exceedance, current harmonic limit exceedance, and temperature limit exceedance.
• 10. Wide target power factor adjustment range.

The technical parameters for the product are: Sampling Voltage: AC220V ±20% (single-phase voltage from a three-phase four-wire system); Sampling Current: AC 0.1A-5.0A (controller enters under-current state if below 100mA); Operating Frequency: 45Hz-65Hz; Under-voltage Threshold: 180V; Dynamic Output: DC12V, 10mA per circuit, common terminal positive, output circuit negative; Static Output: Passive relay output, 250V 3A; Alarm Signal: Passive relay output, 250V 3A; Total Power Consumption: ≤10W; Protection Class: IP30; Connection Method: Plug-in terminal block with screw fixation; Installation Method: Flush mounting with snap-on attachments. For proper function, install this Capacitor Changeover Controller under these normal conditions:

• 1) Altitude ≤2500 meters;
• 2) Ambient temperature -20℃ to +50℃;
• 3) Air humidity ≤50% at 40℃, ≤90% at 20℃;
• 4) Environment free from corrosive gases, conductive dust, and flammable/explosive substances;
• 5) Location without severe vibration.

The wiring diagram is drawn with all functions complete. If a part does not have a wiring port, then that function is not available. Note: The sampling current only supports current transformers with a secondary current of 5A. If you have special requirements, please contact our company.

Three-transformer sampling method (for situations requiring phase-by-phase compensation)

Sampling method for a single current transformer (in cases where phase-specific compensation is not required, all are common-compensation).

Static output (passive contact output)

The AC contactor coil pin A1 is connected to the controller circuit output, and pin A2 is connected in parallel with the V terminal to a different phase sequence. The voltage between phases must match the coil voltage level.

This controller can be equipped with an RS485 communication interface. This interface can be used to connect to a computer or for circuit expansion; only one can be selected. When used for computer connection, our company provides free background testing software. If the circuit of one controller is insufficient to meet the customer's requirements, a circuit expansion module can be purchased separately, in which case the communication interface can only be used for circuit expansion.

Currently, there are three capacity switching methods on the market. The first method is cyclic switching, where capacitor banks use equal capacities. When configured, if there are few circuits, the individual capacitor capacity is large, resulting in low compensation accuracy. If there are many circuits, it increases costs. The second method is arbitrary capacity switching, where capacitor capacities are configured in a random, varying manner. This requires setting the capacitor capacity for each circuit, leading to non-linear compensation, and is cumbersome when there are many circuits. The third method, similar to this controller, uses capacity encoding. This method is simple to set, requiring only the capacity encoding and tiered capacity parameters. These two parameters allow for the calculation of subsequent capacitor capacities, and it offers high compensation accuracy. However, capacity encoding is limited by the number of encoding types. Since this controller has many circuits, the third capacity encoding method is the most reasonable. Currently, this controller only has 12 capacity encoding types. Our company will try to increase the number of capacity encoding types in the future to meet the actual needs of different customers.