Reactive Punishment

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How to Calculate Reactive Penalty?

If there is no information other than the installed power of the facility to be reactive power compensation, the calculation is made as follows. For example, we do not have any information other than that the facility has only 500 kW installed power. Then the synchronization coefficient is taken as 0.60

P = 500 kW * 0.60 = 300 kW.

Since the power coefficient will be increased from 0.6 to 0.97;

S1 = P/cosφ1 = 300 Kw/0.7 = 428 kVA

Q1 = = 306 kVAR

Likewise;

S2 = P/cosφ1 = 300 Kw / 0,97 = 309 kVA

Q2 = = 78 kVAR

Once Q1 and Q2 are found, we can immediately calculate the capacitor.

Qc = Q1-Q2 = 306 - 78 = 228 kVAR Capacitor required

Reagent Ratios

It is compulsory to install a combi meter to measure reactive energy in facilities with a connection power above 9 KVA.

Compensation is mandatory for installations with a connection power above 50 KVA.

Inductance reactive penalty limit 33% for installations with connection power below 50 KVA

Capacitive reactive penalty limit for installations with connection power below 50 KVA 20%

Inductance reactive penalty limit for installations with connection power over 50 KVA 20%

Capacitive reactive penalty limit is 15% for facilities with connection power below 50 KVA.

Reactive Power

Actually, electrical power is expressed as apparent power.Apparent power consists of active and reactive components.Active power (P) is the part that mainly works.Active power is the product of the magnitudes of voltage and current with the cosine of the angle formed due to the phase difference between voltage (V) and current (I) (P = V * I * cosφ). Reactive power (Q) is the part that does not work. Motors, transformers, etc. that create magnetic fields and capacitance devices use reactive power. Reactive power is the product of voltage and current magnitudes with the sine of the angle formed due to the phase difference between voltage (V) and current (I).(Q=V*I*sinφ).

Power factor is the cosine of the angle formed due to the phase difference between the power voltage and the current. It is also the ratio of active power to apparent power.

To better understand reactive power and power factor, we have a very common real-life example.

kW is Operating Power (also called Real Power or Active Power or Real Power). It is the power that powers the equipment and does useful work.

kVAR is Reactive Power. It is the power that magnetic equipment (transformer, motor, relay, etc.) should produce magnetic flux.

kVA is Apparent Power. It is the "vector sum" of KVAR and KW.

To give a real life example;

To better understand these terms, let's look at a simple analogy. For example, on a hot summer day, you will drink a cold foamy buttermilk. The non-foam part of the buttermilk, that is, the actual cooling part, is represented by kW. On the other hand, the foam part is represented by kVAR. In this case, the entire visible power kVA of the buttermilk is the sum of kW and kVAR.

Power factor is the ratio of active power to apparent power;

Reactive Power Compensation

The application made to reduce or eliminate the reactive power drawn from the network is called 'reactive power compensation'. In other words, it is the application of reducing the reactive power drawn from the network to zero, bringing the power factor closer to 1 value and reducing the phase difference between the network voltage and current by meeting the reactive power required by the loads from the compensation elements.

Capacitive Reactive

In other words, it is the reactive power given to the network in systems where more insulating elements are used. In other words, if you have ups, lighting with electronic balance, computer systems, etc. in your system, you are producing capacitive reactive power.

Inductive Reactive

In other words, it is the reactive power drawn from the network in systems where more magnetic field generating elements are used. In other words, if you use electric motors, induction heaters, magnetically balanced lighting, etc. in your system, you are also consuming inductive reactive power if your meter comes before the transformer.

Classical (Contactor) Compensation

The most widely applied compensation system in terms of use in our country is the classical compensation system, sometimes referred to as contactor compensation. The most important feature of this compensation system is that the compensation system has contactors. Contactors are switching circuit elements and devices that perform the opening and closing process in circuit conditions, as we have mentioned in our previous articles (You can review our article titled "What are the Compensation Panel Elements?"). The quality of the material from which the contacts of the contactors, whose basic building block is contacts, are manufactured, ensures the long life of the contactor.

Basically, reactive power control relay, capacitor, automat (fuse) and contactor are used within the classical compensation system (Again, you can find more detailed information about the devices mentioned in our article titled "What are the Compensation Panel Elements?"). The reactive power relay enables the contactors in the circuit to open or close according to the cos φ value transmitted by connecting the K-L ends of the current transformer / transformers to the relay. In this way, capacitors are activated and deactivated according to the situation by means of contactors.

Capacitors are compensation circuit elements used to correct inductive energy, which is one of the types of reactive penalty or reactive cost. In a compensation system, the importance of capacitors is very high according to the characteristics of the system to be compensated. If the capacitors used as three-phase and single-phase are smaller than the required value, that is, if they are small steps (kVAR), the system is penalised from inductive energy consumption under reactive penalty. If the values of the capacitors (kVAR) are greater than the required value, the phase voltage overrides the current and capacitive charge, which is another type of reactive penalty, occurs.

The fact that the compensation panel is built is not a solution not to be subjected to these reactive penalties. For the solution, it is also necessary that the compensation is fine-tuned very accurately and precisely by competent persons. Only in this way the system is correctly compensated and reactive penalties are avoided. For this reason, the selection of panel elements such as capacitors and shunt reactors is very important and material selection should be made correctly.

The advantages of the classical compensation system are that it is cost-effective, all functions in the reactive power relay can be controlled, necessary arrangements can be made without reactive penalty, and all energy can be monitored and controlled.

Dynamic (Thyristor Fired) Compensation

It is a compensation system that has just started to be used in our country. There are 2 types of this compensation system, thyristor or triac. Triacs are used for single phase loads not exceeding 25A. On the contrary, thyristors are used in enterprises with overloads. There are A1, A2 and Gate terminals.

In the installation of the Dynamic (Thyristor Fired) Compensation system, thyristor or triac is used in addition to the classical compensation as mentioned above according to the load condition of the enterprise. The reactive power relay sends a trigger voltage to the gate end of the thyristor or triac in the circuit according to the cos φ value transmitted by connecting the K-L terminals of the current transformer/transformers to the relay and thus enables the thyristors or triacs to pull or release. In this way, capacitors are switched on and off. The basic logic is the same as the contactor.

Since thyristors or triacs are switched on and off in very short periods of time (milliseconds), they cause damage when switching on capacitors. In order to repair and eliminate this damage, zero-crossing circuits are used. Thanks to these zero-crossing circuits, when the trigger voltage is applied to the gate, the input voltage at A1 is captured at zero volts and applied to the capacitor. The most important advantages of Dynamic (Thyristor Fired) Compensation are that they enter and exit the circuit very quickly, work silently and do not need maintenance. It is a little more costly than classical compensation.