Bryan Texas Utilities’ Technical Requirements for Distributed Generation Interconnection for Facilities Under 100 kW

1.      Manual Disconnect 

A manual load break disconnect switch that provides clear indication of the switch position and is appropriate to the voltage level shall be available at the customer's main service point to provide a separation point between the customer's electrical generation system and Bryan Texas Utilities’ (BTU) electrical system.  BTU will coordinate and approve the location of the disconnect switch.  The disconnect switch shall be easily visible, mounted separately from the metering equipment, readily accessible to BTU personnel at all times, and capable of being locked in the open position with a BTU padlock.  Bryan Texas Utilities reserves the right to open the disconnect switch isolating the customer's electrical generating system (which may or may not include the customer's load) from BTU’s electrical system for the following reasons:

a.       To facilitate maintenance or repair of BTU’s electrical system;

b.      When emergency conditions exist on BTU’s electrical system;

c.       When the customer's electrical generating system is determined to be operating in a hazardous or unsafe manner or unduly affecting BTU’s voltage waveform;

d.      When the customer's electrical generating system is determined to be adversely affecting other electric consumers on the BTU system;

e.       Failure of the customer to comply with applicable codes, regulations and standards in effect at that time;

f.       Failure to abide by any contractual arrangement or operating agreement with Bryan Texas Utilities.

2.      Voltage 

BTU shall endeavor to maintain the distribution voltages on the electrical system but shall not be responsible for factors or circumstances beyond its control. The customer shall provide an automatic method of disconnecting generation equipment from BTU’s electrical system within 10 cycles should a voltage deviation greater than +5% or -10% from nominal be sustained for more than 30 seconds (1800 cycles) or a voltage deviation greater than +10% or -30% from nominal be sustained for more than 10 cycles.  If high or low voltage complaints or flicker complaints result from the operation of the customer's electrical generation, the customer's generating system shall be disconnected until the problem is resolved.

3.      Frequency 

BTU shall endeavor to maintain a 60-hertz nominal frequency on the electrical system. The customer shall provide an automatic method of disconnecting generation equipment from BTU’s electrical system within 15 cycles should a deviation in frequency of +0.5Hz or -0.7Hz from nominal occur.

4.      Harmonics 

In accordance with IEEE 519, the total harmonic distortion (THD) of voltage shall not exceed 5% of a pure sine wave of 60-hertz frequency or 3% of the 60-hertz frequency for any individual harmonic when measured at the point of interconnection with BTU’s electrical system. Also, the total current distortion shall not exceed 5% of the fundamental frequency sine wave. If harmonics beyond the allowable range result from the operation of the customer's electrical generation, the customer's generating system shall be disconnected until the problem is resolved.

5.      Flicker           

The distributed generation facility shall not cause excessive voltage flicker on BTU’s electrical system. This flicker shall not exceed 3% voltage dip, in accordance with IEEE 519 (Section 10.5), as measured at the point of interconnection.

6.      Power Factor 

The customer's electrical generation system shall be designed, operated and controlled at all times to provide reactive power requirements at the point of interconnection from 0.95 lagging to 0.95 leading power factor.  Induction generators shall have static capacitors that provide at least 95% of the magnetizing current requirements of the induction generator field.  BTU may, in the interest of safety, authorize the omission of capacitors.  However, where capacitors are used for power factor correction, additional protective devices may be required to guard against self-excitation of the customer's generator field.

7.      Loss of Source 

The customer shall provide UL approved protective equipment necessary to immediately, completely and automatically disconnect the customer’s electrical generation equipment from BTU’s electrical system in the event of a fault on the customer's system, a fault on BTU’s system or loss of source on BTU’s system.  Such protective equipment shall conform to the criteria specified in UL 1741. The customer’s generating system shall automatically disconnect from the grid within 10 cycles if the voltage on one or more phases falls and stays below 70% of nominal voltage for at least 10 cycles. The automatic disconnecting device may be of the manual or automatic reclose type and shall not be capable of reclosing until after BTU’s service voltage and frequency are restored to within the normal operating range and the system is stabilized. 

8.      Coordination and synchronization 

The customer shall be solely responsible for coordination and synchronization of the customer's electrical generating system with all aspects of BTU’s electrical system, and the customer assumes all responsibility for damage or loss that may occur from improper coordination and synchronization of its generating system with BTU’s electrical system. 

9.      Metering 

The actual metering equipment required, its voltage rating, number of phases and wires, size, current transformers, number of input and associated memory is dependent upon the type, size and location of the electric service provided.  In situations where power may flow both in and out of the customer's electrical system, power flowing into the customer's electrical system will be measured separately from power flowing out of the customer's electrical system.  BTU will provide, subject to existing rate schedules at the time of application, the metering equipment necessary to measure capacity and energy delivered to and from the customer. 

10.  Interconnection Study 

If BTU determines that an interconnection study is necessary, BTU shall perform (or have performed by an outside engineering firm) the study under terms and conditions agreed upon by both the customer and BTU and at the customer's