## Reactor

Reactor Object

The Reactor element is an extremely flexible and powerful circuit element. The Reactor element is implemented with basically the same philosophy as a Capacitor (and a Fault object). It is a constant impedance element that may be configured into a variety of connections. Like the Capacitor, the second terminal defaults to a Wye connection to ground if not specified. In that case, it is flagged as a Shunt element. It is a constant impedance element entirely represented by its primitive Y matrix.

A Reactor object can have frequency-dependent R and L by supplying an appropriate per-unit XYCurve object. You can put a Reactor in series with another circuit element to give the element frequency dependence. This might be common for a Transformer for harmonics studies. If a Line object is defined by a LineGeometry object, frequency-dependence is often automatic. However, if defined by a LineCode object you can use a Reactor element, appropriately defined, to impart frequency dependence.

The reactor may be conceived as a series R-L or a parallel R-L connection (see Parallel property). By default it is an inductance with series resistance. You may also specify a resistor, Rp, in parallel with the entire branch. These options allow the Reactor impedance characteristic to have different frequency response characteristics, which are often useful for some Harmonics-mode simulations, particularly for filters. In the case of a shunt reactor, the Rp value is used for no-load losses.

Zero-impedance devices cannot exist in OpenDSS. However, either R or X can be zero in this model, but not both. A Reactor element can be used for source equivalent or other equivalent impedances where the capacitance of a Line element is unnecessary. Use a 1-phase reactor to model neutral reactors in transformers, generators, or loads.

By default, the Reactor has no coupling between the phases. Shunt reactors would typically be defined by kV and kvar properties, similar to a capacitor. Series reactors without mutual coupling would be defined by the R and X properties. Of course, either could be used in all circumstances.

You can use Reactor objects to represent lines and switches. However, keep in mind that you do not get any shunt capacitance as a Line element would naturally give. Thus, it is easier to accidentally create isolated islands with no conductive path to ground. This will result in Y matrices that will not invert and you will get floating-point errors.

Note that if the connection is specified as “delta” only the first terminal matters; there is no second terminal. This applies only to shunt reactors. By leaving the Conn property as wye and specifying both terminal connections explicitly, nearly any reactor configuration can be achieved. Mutual coupling between phases can be achieved by specifying Rmatrix and Xmatrix properties. Note that the matrix specification is mutually exclusive with the other means of specifying the reactance values. Of course, the Rmatrix and Xmatrix properties may be defined with zero mutual coupling. The Parallel property applies to the Rmatrix and Xmatrix specification.

phases |
Number of phases. |

bus1 |
Name of first bus. Examples: |

bus2 |
Name of 2nd bus. Defaults to all phases connected to first bus, node 0. (Shunt Wye Connection) Not necessary to specify for delta (LL) connection |

kv |
For 2, 3-phase, kV phase-phase. Otherwise specify actual coil rating. |

kvar |
Total kvar, all phases. Evenly divided among phases. Only determines X. Specify R separately |

conn |
={wye | delta |LN |LL} Default is wye, which is equivalent to LN. If Delta, then only one terminal. |

Parallel |
{Yes | No} Default=No. Indicates whether Rmatrix and Xmatrix are to be considered to be in parallel. This makes a significant difference in harmonic studies. Default is series. For other models, specify R and Rp. |

R |
Resistance (in series with reactance), each phase, ohms. |

Rmatrix |
Resistance matrix, lower triangle, ohms at base frequency. Order of the matrix is the number of phases. Mutually exclusive to specifying parameters by kvar or R. |

Rp |
Resistance in parallel with R and X (the entire branch). Assumed infinite if not specified. |

X |
Reactance, each phase, ohms at base frequency. |

Xmatrix |
Reactance matrix, lower triangle, ohms at base frequency. Order of the matrix is the number of phases. Mutually exclusive to specifying parameters by kvar or X. |

Z |
Alternative way of defining R and X properties. Enter a 2-element array representing R +jX in ohms. Example: Z=[5 10] ! equivalent to R=5 X=10 |

Z1 |
Positive-sequence impedance, ohms, as a 2-element array representing a complex number. Example: Z1=[1, 2] ! represents 1 + j2 If defined, Z1, Z2, and Z0 are used to define the impedance matrix of the REACTOR. Z1 MUST BE DEFINED TO USE THIS OPTION FOR DEFINING THE MATRIX. Side Effect: Sets Z2 and Z0 to same values unless they were previously defined. |

Z2 |
Negative-sequence impedance, ohms, as a 2-element array representing a complex number. Example: Z2=[1, 2] ! represents 1 + j2 Used to define the impedance matrix of the REACTOR if Z1 is also specified. Note: Z2 defaults to Z1 if it is not specifically defined. If Z2 is not equal to Z1, the impedance matrix is asymmetrical. |

Z0 |
Zero-sequence impedance, ohms, as a 2-element array representing a complex number. Example: Z0=[3, 4] ! represents 3 + j4 Used to define the impedance matrix of the REACTOR if Z1 is also specified. Note: Z0 defaults to Z1 if it is not specifically defined. |

RCurve |
Name of XYCurve object, previously defined, describing per-unit variation of phase resistance, R, vs. frequency. Applies to resistance specified by R or Z property. If actual values are not known, R often increases by approximately the square root of frequency. |

LCurve |
Name of XYCurve object, previously defined, describing per-unit variation of phase inductance, L=X/w, vs. frequency. Applies to reactance specified by X, LmH, Z, or kvar property.L generally decreases somewhat with frequency above the base frequency, approaching a limit at a few kHz. |

LmH |
Inductance, mH. Alternate way to define the reactance, X, property |

Properties inherited from the circuit element class:

normamps |
Normal rated current. |

emergamps |
Maximum current. |

repair |
Hours to repair. |

faultrate |
No. of failures per year. |

pctperm |
Percent of failures that become permanent. |

basefreq |
Base Frequency for ratings. |

enabled |
{Yes|No or True|False} Indicates whether this element is enabled. |

like |
Make like another object, e.g.: |